I didn't make clothing / slotting for a long time ; but it used to be like
this :
- First your proficiencies are compared to the artifact list to lower the difficulty . For exemple for a mined gem like Dravite which is a 15 to 5 Law& Lore difficulty : with 0 in L&L you''ll have a 15 "base difficulty" so 85% chance of slotting in 0 difficulty clothes . With thousands of L&L you''ll have a 5 "base difficulty" so 95% chance of slotting in 0 difficulty clothes. With 50 L&L you should have 10 "base difficulty" : (5+ (15-5)/2) ; with 100 L&L you should have 8 "base difficulty" : (5+ (15-5)/3), with 150 L&L 7.5 (5+ (15-5)/4)...
- After that you check the cloth difficulty. If you have a 90% "base difficulty" , then you'll have 90% "final" slotting chance in a 0 difficulty cloth , 85.5% chance in a 5 difficulty cloth (90 base x95%) , 81% chance in a 10 difficulty cloth (90 base x90%) ... 67.5% chance in a 25 difficulty cloth (90 x75%)
Here's a older explanation of how much C&D you'll need in case of several proficiencies involved : "
First, you need to calculate Effective Matched Proficiency - it is square root of sum of squares of your proficiency values of matched proficiencies in clothing and artifice - SQRT(Pr1^2 + Pr2^2 + ... + Prn^2)." : no idea if it's still currently calculated like that .
1% is already pretty good , not sure you can have 0% because there will be a rounding involved.
Bjebr