Help me decide - Big or small bolt pattern?

Car looks absolutely killer, my only thought is that it is probably not cheap or easy to get parts where you are, and the simplest thing to do is the Kelsey Hayes small bolt original disc setup. There are a couple of members here that sell them from time to time.
On my 1970 Dart I ran them with the original 10 inch drums without any problems as a daily driver and occasional drag strip pass. Unless you are planning on getting into autocross or serious drag racing you will likely be fine with that setup. Someone mentioned Pirate Jack rear disc conversion as well, May be a good option too.
I also had sbp rallye wheels on my 70.