Wow Cheeker, that sounds like quite the adventure! Glad that you are ok and made it home safely. Your "remedy" was quick genius for the situation.
My thoughts are:
Dual Master-Yes
Riveted drums-Yes
wheel cylinders and brake hoses-Yes
After that, see how it performs and decide if you wish to add the booster.
I did the upgrade to dual master, wheel cylinders and Booster. It is sensitive or touchy, but I have not drilled the one inch lower hole yet. I have the drums all around and it stops nicely.