15x8 w/ 4.5” BS on front/good handling size?

Yeah, I did say on the factory front end .............. and I don't see OP setting up his "cruiser" like yours.
However;
I applaud you for making it work, cuz;
I made it work on the factory 68 to 72 front end, with the KH 4pots, at 4.25 bs; and I know how much work that was.