This old plane was built in 89 but I still do the same thing with my planes today. It's built around a YS 1.20 and was designed for the OS .60 two stroke. It was going to be nose heavy so three servos were located aft but it was all done in the bones. All the gear was located to achieve the CG then hard mounted before covering. Even with the covering done you may still be able to mount the rudder and elevator servos as far back as they will fit. Two elevator servos on the outside around the stab and the rudder servo inside as far back as it will go inside a hatch. The only thing I have in the center section of the fuse is the throttle servo, fuel tank and a battery. The switch is mounted behind the canopy too.
I know it's a pain to do now but that is a lot of lead. Then again I have about a pound of the stuff on the nose of my Swoose but when the plane was designed the guy had to use that much to get the CG on the original too, just a lot of fuse and tail feathers behind the CG. You do what you gota do.