What's the lowest stat ele pierce that is worthwhile to ws 10%? I would define worthwhile as using the white scrolls does not result in a loss for the scroller on average. Example: Clean ele pierce worth 10 ws. The finished ele pierce should be able to sell for 80 ws. 1 slot = 10 ws.
I cannot give you an answer to your question. Allthough I would like to point out that your maths is incorrect. You are expecting to use ~6.58 ws per slot, not 10.
Respectfully, your math is flawed. It is expected to take 10ws per slot, not log(0.5)/log(0.9) =~ 6.58ws per slot. 6.58 is the number of ws it takes to pass a slot 50% of the time, but it's not the average number of ws it takes. If you try applying your math on 50% scrolls, it will be apparent that it doesn't work. log(0.5)/log(0.5) = 1. While it is true that you always have a 50% of passing the next ws, it is hopefully obvious that it would take on average 2ws per slot.
