brake booster help

[Vortech]

Ok, finally decided to pick up booster and master cylinder for dual power drum brake setup. I bought a used setup from craigslist. Guy said it was pulled from a 1965. He said booster was new, looks new. Question I have is the following.
1) when I disassembled to clean up master cylinder to paint, I noticed a lot of corrosion on inner cylinder. I also tried to push piston in and it wouldn't budge. Booster appears to work fine with master cylinder removed. Can Spray withh something to try and free it up

2) Is this the correct master and booster combo for drum drum?

3) do I need to use proportioning valve for drum drum? Or can I just remove
4) Is the shaft for the piston long enough, see pics. Seems like it is too short to activate piston when and if I free it up.



Thanks,