The 71/73 booster is not available in the repop world that I know of.
In the event that you are in for a rebuild of the brake booster, here are the guys I used: https://boosterdeweyexchange.com/
Well respected outfit in the classic car world.
Everyone has an opinion on brand of carb and proper size. Next to oil selection, it is a common conversation at any gathering of car guys; online or in person it is always fun.
As far as sizing, I generally go with what the calculators/formulas recommend. Unless you are going to regularly play...
Welcome from North Idaho! I spent some years in my childhood in Bad Hamburg near Frankfurt. I look forward to hearing more about your Mustang's progress.
How great to be able to ring it out once in a while on the Autobahn!
Per the Ford service manual you don't need to disassemble the dash. I was able to wiggle my heater box back in place fully assembled with all clips in place.
As I recall I did not have the carpets or seats in the car (or the side kick panel & glove box). This gave me a tad more room to get...