If you go for 120 you will have 5% success rate, you dont get enough luck to get more. {103-(current ench%+ench material%)}+(luck100per1%) ※lowest success rate 5%
I have 1418 luck i believe. That's full m33 luck gear (armor, gloves, boots +1 gp, ammy 93%, and skill cape +1). The number of PC's needed to make a piece of 120 gear depends on how the rng rolls for you. some people have used just 1 to make a 120 and others have used of 40 and still having gotten it to 120. Solely depends on how "lucky" you are. whenever you try to actually hit 120 ie. 105 to 120, 108 to 120, 111 to 120, 114 to 120 and 117 to 120 the success rate is 5%.
i've never seen someone use 1 Pc to get 120% enchant item, even with a lot of chance, just for up an ammy 90% it take atleast 4/5 PC. So to get 120% enchant you'll need ammy 102% (1500 lucky) or more and 10/15 PC.
Enchanting here is pain in the a$$! i was hardly able to make 90% blade, with 1200 luck! broke so many items in the process.. not worth spending on PC thou! unless we are talking about higher % or leet, or both