Cass, Is your offset bracket to hemi booster dimensions or to the standard B body booster stud pattern? Some of the folks who made the replica hemi to hemi booster spec are no longer making them. Some of the newer stuff is standardized at the B body non hemi dimensions.

If you go original 66-69 B body, the rotor is available, but you need to find good hubs and you would need the 66-69 spindles and the 4 piston Bendix caliper. Not impossible but harder and more expensive.

If you go 70-72 KH type that is easier to source spindles, calipers, brackets, rotor. Rotors are one piece and Calipers are cheap even new. Rotors are 10.98". This would mimic a 70 B body with disc, uses same Bendix booster and MC type. If you go hemi booster and bracket you get the MC with Ports to the fender. This would probably be the least expensive route that meets your needs to swap wheels and would look OEM though not 69 OEM. If not full OEM, going with DR Diff assembly is OEM like at reduced cost of the OEM Booster and linkage.