Adding CJ7 Brake Booster

[heinsite]

I am going to add a brake booster to my now manual brake system. I want to buy new bracket, booster, Masterand would like some information on which size and options to buy. The big jump in price is 9in to 11in. I read all the threads which ultimately never answer the questions asked below (unless I'm overlooking them), other than buy the biggest or best you can, and make sure you have clearance, which I understand.
I have a IL6, 3-4 lift, 33in tires..want easy braking so my petite wife can drive also..This is a street rider, seldom off road if matters. Thanks in advance!
Questions:

1. Sizes: 7in, 8in, 9in, and 11in...is there a point you don't gain between sizes?
   
2. With our without Proportioning Valve?

 

[Torxhead]

With that size tire, by all means get the big booster. I recently replaced my oem prop valve with one made by Crown and noticed quite a difference in stopping alone and have whatever style booster that came with the Jeep. I did install an adjustable push rod for the system for a finer adjustment some time ago.