1970 front disc brake conversion

[picklito]

It's time to do the front swap to discs. It's a 70 GMC big block 2wd 6-lug with power drums. Want to keep the 6-lug and stock height. I'm finding MANY shops selling kits and parts, and the Brothers kit is currently on sale. Does anybody know how large the discs are in the various kits? I'm seeing 12" from McGaughy's. How large are the Brothers, CPP, POL, ECE, etc? How large is a stock GM setup for comparison?

I don't want to go with one of the "big brake" kits, I just want a sufficient size "OE" style replacement.

Any "must avoid" kits out there?

Thanks!