In a bolt plus you will have to do a lot of work to get BKP's in.
To get them in my contour I had to widen the cavities slightly (they were too narrow neck to bridge), grind a large radii onto the corners of the BKP's, slip the triangular tabs (didn't know that was standard as the schema I had seen showed squares), drill out the ring mount holes to be direct mount, and maybe drill a center hole on the bass side, can't remember if it was already there or not.
I did most of this with a rotary tool and a grinding tip (like a barrel of grinding stone).
This was all for open coil pickups too, I skipped covers for obvious reasons. By my measurements I should have had enough space but alas something funny happened and my 1mm of place didn't. Well it did, but it was too tight for adjustment purposes (very snug), the winding exceeded the edges of the baseplate with tape on was the issue there (Rebel Yells).