Yes totally overkill. imo 65% with any 10% crit synergy from party is perfectly fine. I don’t know a lot about this game yet but by the number alone 75% seem ok, might be 80% if you really like it, but 90+ seem overkill.
yes, if you’re instant cast remove precise dagger for a dmg engraving like hit master/cursed doll/grudge. or if you have one of those already and are running raw dmg tripods (magick amp) over final strike, then KBW is an excellent choice as well
if you’re a casting reflux, you may want to opt for removing adrenaline instead due to higher cds and lesser APM.
i am using reflux, grudge and hit master. You can check hit master/grudge stones, at least in my server they were on reasonal price. As 4th engraving you can take cursed doll as well to max your damage.