Recommend a Brake Booster / MC Please

[Luke87gt]

Hi guys, my truck is 69 i6 with 4wheel drums (manual)

I will be upgrading to CPP drop spindles and front 6-lug brake upgrade (I plan to add power brakes). Rears will remain drums.

Can you recommend a MC/Booster combo for me, preferably something I can buy on Rockauto? Should I be purchasing a 71-72 booster/MC? Any particular size booster recommended?

Also, if someone can steer me in the right direction for the proportioning valve below the MC that would help? Can I reuse the stock one?

Thanks