Need upgrade guidance

Right now I'm rolling on 13" wheels with 9" drum brakes and a single res master cylinder (It's new, but... why?). Point is the stopping is less than ideal.

My father suggested I upgrade to 14" wheels with 10" drums and a twin res master cylinder, but after looking at the Scarebird upgrade I don't know. The current master cylinder is going to be replaced, regardless.

1) Would 10" brakes make enough difference to justify the swap or should I save my coppers and go to disc?
2) If I were to go with larger drum brakes what would be an idea donor?

Sorry for the basic questions. I've been searching the boards all morning and taking notes, but I figured I'd still ask.

I know there is no budget when it comes to safety, but the fact is if the money isn't there I can't spend it so I need some ideas on how to bring this 170ci-powered maroon hulk to a stop.

As always, thanks for the advice!

Jim