8.8 Swapped in, Brakes need help

I've used this site for years, and have always found what I needed without posting, but all things come to an end I guess.

I recently finished swapping in a 2000 Exploder 8.8 axle (thanks for the info on that!) into my '97. Everything is working well, but I don't have enough brake pedal. I have put it to the floor to get solid(?) braking. Also the brake light on the dash comes and goes during stops, especially if I pump the brakes.

I've seen multiple threads that discuss replacing the MC, pulling the o-ring on the PV or adding an adjustable PV. I'm leaning toward installing the E350 MC, but haven't seen where anyone did that on a post '95 XJ that come with "better" braking systems. Any opinions on if the E350 MC will do what I want?

how well did you bleed the system? I was just reading a thread (not sure if it was here or not) about the proportioning valve being the main culprit in weak brakes even after a thorough bleeding.

Did a gravity bleed for a couple hours, and about 4 rounds with pressure.
Pretty sure it isn't air, but I can bleed them some more.