Here are the parts I have, what's the best approach?

I have a 65 Dart,360,4 speed and it has the 7 1/4 rear. I want to upgrade the rear to the 8 3/4, here are the parts I have.

Bare rear 8 3/4 housing with the adjusters
741 pumpkin, peg leg, 29? ratio
SBP axles that need bearings
10" BBP backing plates and drums
The front brakes are factory SBP disk.
I have a full set of SBP Rally wheels that I have just had blasted and repainted the argent silver, also have the cone rally centers that i have just repainted the textured argent and added the new spun aluminum center disk appliques.

I guess the question is, do I go SBP on the rear? the problem is that I don't have the backing plates or drums, are they hard to find?, and get rid of the BBP backing plates and drums.
If I go BBP, I have to get 2 BBP rally's and redo them, and get rid of the axle's I have and two of the rally wheels I have just redone.
What would You do?