cumn thru,
Welcome to UCD Hatch Cutters. I've been flying my UCD 60 with the CG at 5 1/2 inches and it took a hatch cutting to get it there. It surprising how little effect moving the battery around in the radio compartment had on CG. I thought I was going to run out of fuselage before I got the CG right. My hatch in the bottom of the fuselage is centered 29 1/2 inches back from the wing leading edge.
I moved the CG to 5 1/2" and made engine thrust angle changes with hopes of making the UCD 60 do 3d as well as my UCD 46. It helped a lot.