It would work fine and you should not need an adjustable pushrod. The piston in the cylinder ends up in the same spot relative to the firewall with the adapter plate.

You should use residual pressure valves with drum brakes. There is talk about how they are not needed if the wheel cylinders have expanders. Save yourself the trouble and be safe. Just use them. They do shorten up pedal travel a fair amount too, and that alone is a big reason to use them.

Having the pedal get mushy while the fluid level in the master rises is just a hassle no one needs, and thats what happens when the wheel cylinders start gulping air.

I have seen new wheel cylinders lately that DO NOT have the expanders, they were Centric brand. With all the imported junk in the market things like this are not getting better.