Jamesray

My illy has racked up about +650 to spell damage over various pieces of gear and I'm noticing only about 35% of the actual value has been added when I'm removing items individually.

I was under the impression the scale has to do with the proportion of total damage the spell is doing, IE a warlock with a 3K nuke can handle a lot more BoE and get full benefits than me with a 1.4K nuke, right?

At this point I've done most of the KJ solo quests and some heroic instances and have quite a selection of BoE and/or spell crit gear to mix and match, just thought I'd see if anybody feels there is an ideal number to hit before trying to swap out BoE for spell crits, or if there was some sort of conversion rate.

Teevee

Correct, once you get up around 650 - 700 +spell damage mod, it is a waste to go more as the returns are too minimal vs +crit chance.

Try to hover around 650 - 700 and get as much crit as possible, check out Pinski's post in the sticky for RoK gear.