Potent weapon scrolls currently available?

Scroll traces are meant to replace scrolls entirely, consequently, they've seemed to have stopped producing event scrolls since their release.

If you're going for perfection, you should probably just do 15%s all the way with clean slates, probably on a character with max dilligence, farming lucky day scrolls whenever you can. Do elite bosses for safety scrolls, unless you're okay with buying them as a service.

I've embarked on the journey to create a claw for myself as GAZED has little to offer. I landed 2/4 of the aforementioned 50% scrolls for 8 Attack and 1/4 30% Spell Traces for 7 Attack. I managed to pass a few 10% no boom Clean Slates and another 2 30% Spell Traces passed on the claw (+5 Now, 123 Attack). I plan continuing 30% Traces for the next 4 slots, finishing the last with one of the 15% to have a 160 Attack pre-Enhanced claw.

My biggest question around finishing the claw is Hammers. Should I go the route of the in-game 50% Hammers and one/both fail, will I be able to restore the slot with a Clean Slate?

And is Willpower bonus additive or multiplicative?