4 wheel drum brake balance.

[ChevyBrad]

Hey guys, I have a 3800 1 ton single rear wheel with factory original front axle and brakes that I swapped a rear dana 60 full floater axle from a 77 F250 into a little while ago. I drove the truck around for one summer and noticed I had issues with maintaining proper brake balance, front to back. I have a dual master cylinder and I had originally installed a manual proportioning valve in the rear line to reduce the pressure but, the problem is that the front brakes are manual adjustment while the rear is automatic. I found that as I drove the truck, the front brakes would wear slightly and then the rears would start wanting to lock up first in the rain. I could tighten the proportioning valve then to keep driving until I adjusted the front again but, that's not a fix. Anybody have any ideas or tried to run a similar set up before? I was considering trying to make the rear manual adjustment as well but I do not think I can. Would an automatic proportioning valve work by delaying the rear brake application until after the fronts started working? Does anyone know if I could convert my rear dana 60 to manual adjustment as well so everything backs off at the same rate? Thanks.