Front/rear balance after front disc swap

You should install a proportioning valve. Using the factory disk brake PV/safety switch is an easy swap. Or you can add an aftermarket PV in the rear brake line, but that's a lot more work. Changing the rear wheel cylinders is NOT the same thing. Yes, it affects the front/rear brake bias, but the valve does it dynamically. 10" rear drums with the factory front disks should work fine with the factory PV (that's the factory set-up) -- no need to swap wheel cylinders.