Which Brake Booster?

Certainly looks to be Midland-Ross dual diaphragm, is correct for 67 power brakes.
If I were in your shoes I would consider only these options.
Find the parts required to rebuild it myself or find a local rebuilder to do it for me.
Change to manual brake master cylinder only.
Majority of performance camshafts wont produce enough vacuum to support power booster anyway. Consider that only if you're considering a performance build.
Good luck.