Hi. Some further information for you all, after discussions with Snicker, and some more indepth reading of the code and spreadsheet simulations.
First, remember there are 3 factors for skillgain chance:
1. 50% of the chance comes from the SUCCESSFACTOR
successchance = (REALskill  minskill) / (maxskill  minskill) where min and maxskill are the min and max skills you can gain at with that event or item. So for instance casting a level2 spell would be 9 and 49you can't gain skill if you're < 9 real, and you can't gain above 49 by casting that spell. Now, the successchance ISN"T your GAINCHANCE factor, but it is used to calculate it:
successfactor = (1  successchance) * .5 if you SUCCEED, or *.2 if you fail. Since your fail/success ratio is exactly the same as your successchance, as successchance is just compared against a random 0100 percent, at any given REALSKILL you can get a "normalized" value for this factor. That is, you have successchance of it being the x*.5 num, and you have 1successchance of it being the x*.2 num, so multiplying each result by it's probability and adding the two for a total probability of 1.0 gives a normalized answer based on the random curve. Which devolves to this:
(((1  successchance)* successchance) / 2 + ((successchance)* (1successchance)) / 5 ) ... lets call successchance s...
(s  s*s) / 2 + (s  s*s )/ 5
I ran this number for REAL skills from minskill to maxskill, and I'll tell you more about this later.
2. 25% comes from your totalskills factor
(TotalSkillCap  TotalSkillsbase) / TotalSkillCap
i.e for a guy at 695 on a 700 char: 700695 / 700 = 5/700
3. 25% comes from your particular skill baseskill factor.
(SkillCap  Skillbase) / SkillCap
i.e. a guy @ 90magery with a 120 powerscroll: 12090 / 120 = .25
Now, remember there are TWO kinds of skill being looked at here, your BASESKILL, and the "REALSKILL", ie the value the game checks for success. An example, and in fact the one prompting this post, is magery. Say your magery is 70, and you equip a 25 WAND. Your BASESKILL is 70, your REAL skill is 45. If you were to wear some +20 jewels instead, your REAL skill would be 90.
Now, the BASESKILL is what is checked for the last two skillgain factors, your totalskill and baseskill factor as I call them above. So, for 50% of your gainchance, it doesn't matter WHAT you do with jewelry or mageweapons etc., it just matters how close to your two caps you are. But for the OTHER 50% of your gainchance calculation, REALSKILL is used, and it is ONLY USED in comparison to whatever act you are doing's MINIMUM SKILL to gain and MAXSKILL to gain.
Let's take magery for an example. If you use jewels to increase your skill, OR use a wand to decrease skill... it doesn't MATTER for your success chance!!Nor that skillgain factor!! Why?? because realskill is ONLY compared against your spell's min and maxskill, it's not absolute! So long as you choose your spell wisely in comparison to your REALskill, that's all that mattersagain,
successchance = (REALskill  minskill) / (maxskill  minskill)
so don't befooled thinking higher realskill from jewels means higher gainfactors it doesnt.
success gainfactor
The runuo code for spells, min and maxskills, is :
Quote:
private const double ChanceOffset = 20.0, ChanceLength = 100.0 / 7.0 ;
public virtual void GetCastSkills( out double min, out double max )
{
int circle = (int)m_Info.Circle;
if ( m_Scroll != null )
circle = 2;
double avg = ChanceLength * circle;
min = avg  ChanceOffset;
max = avg + ChanceOffset;
}
which when cranked gives a 40 point range for each spell level:
circle minskill maxskill 1 5.7 34.3 2 8.6 48.6 3 22.9 62.9 4 37.1 77.1 5 51.4 91.4 6 65.7 105.7 7 80.0 120.0 8 94.3 134.3

Now, when training a skill, we already know that to optimize the skillcap factors we need to:
1. LOCK TOTAL SKILL LOW!
2. Eat a PS to maximize the baseskill factor
but how do we potentially more important 50% of the gainchance equation, successchance factor? Our only choice, and what is always argued, is WHAT to make or cast at WHAT skill. I generated a probability table and cranked it through an excel spreadsheet, looking at the successgainfactor at each skill level from MINSKILL to MAXSKILL. Here is a table for magery. The SKILL is your skill ABOVE the minskill. So, where skill = 1, if you were casting a level 7 spell, that would mean your realskill was 81. The successchance is NOT the magery successchance, but a \"successchance\" that is just used for skillgainfactor calculation in runuo. Finally, the skillgainfactor is the number you're interested in maximizing via your choice of spells to cast, when:
skill success sgfactor 1 0.025 0.017 2 0.050 0.033 3 0.075 0.049 4 0.100 0.063 5 0.125 0.077 6 0.150 0.089 7 0.175 0.101 8 0.200 0.112 9 0.225 0.122 10 0.250 0.131 11 0.275 0.140 12 0.300 0.147 13 0.325 0.154 14 0.350 0.159 15 0.375 0.164 16 0.400 0.168 17 0.425 0.171 18 0.450 0.173 19 0.475 0.175 20 0.500 0.175 21 0.525 0.175 22 0.550 0.173 23 0.575 0.171 24 0.600 0.168 25 0.625 0.164 26 0.650 0.159 27 0.675 0.154 28 0.700 0.147 29 0.725 0.140 30 0.750 0.131 31 0.775 0.122 32 0.800 0.112 33 0.825 0.101 34 0.850 0.089 35 0.875 0.077 36 0.900 0.063 37 0.925 0.049 38 0.950 0.033 39 0.975 0.017 40 1.000 0.000

You can see that the skillgainfactor starts low, rises to max halfway through the range, and symetrically drops off again. Since the entire formula is linear, and is composed of a factor and it's exact inverse, this perfect symetrical curve makes sense. Obviously we want to work around the exact center for the maximum gain over time. For magery, you can see that each new level is about 14 skillpoints higher than the last one. Therefore, we would like to jump levels every 14 skillpoints... but when? Well, we want those 14 skillpoints to be centered around the middle of the curve which is 40 wide centered at 20... so from 13 to 27! Therefore, we should be training magery in the following method:
circle minskill maxskill start skill this level 1 5.7 34.3 0 2 8.6 48.6 22 3 22.9 62.9 37 4 37.1 77.1 51 5 51.4 91.4 65 6 65.7 105.7 80 7 80.0 120.0 94 8 94.3 134.3 108

This may be counter to what most people do, but for RUNUO, it's the formula. Now, when you can no longer cast cast cast, but must wait to generate mana, you can obviously refer to the gainfactor chart above to see what your tradeoff will be if you keep using lowered mana spells further into their skillrange instead of changing up.
The clear answer for magery is this: 1. don't use jewels to increase your skill, it adds NO GAINCHANCE, but just increases the level of spell youmust cast and thus the amount of mana and wait time, thus massively reducing the number of attempts you can do over time, thus lowering your gainrate.
2. DO use a mageweapon to lower your skill, for the opposite of all the reasons just given above.
3. follow the "what level to cast when" table above.
[/SnickerPwning]