What is going to happen when I remove the master cylinder?

Just to add here for somebody that may not know the difference.
Disk /drum master cylinder has one resivour larger than the other. Larger is disk requires more fluid than the drum 1/2.

Drum/ drum master the resivour s are the same size as the wheel cylinders are typically needing close to the same amount of fluid. Also I learned because brake fluid gets hot and disks get even hotter. The extra fluid is also a basic type radiator. Also the larger qty of fluid is a safety margin if you lost brakes you have so many stops before you ran out of brake fluid.
Technically the proportioning valve has a valve that detect the lack of pressure from the leak and shuts down that pressure.

It’s not so complicated. Do more reading thru the search as a lot of conversions have been discussed on this board about this matter. Education is only a “click”away. Good luck.
Joe