Nick, Good looking build you've got going on here. Moving the wheel axle inward will give you more balance on the weight. Think of the axle being the pivot point on a lever (fulcrum). I considered the weight of my FB and the weight of the cook chamber and placed my axle inward toward the CC. No calculation here just a WAG of where to locate the axle. I just welded it all up in one piece and I can easily move it around. (it feels like about a 20lb lift ). If you add a handle or shelf (added length) then the lift weight will be lessened even more.
"I might have to rethink the method of moving it. I was originally going to just lift it on the cc end and push it like a wheel barrow but this thing is getting heavy"
Could move the wheels to the inside edge of the FB or even weld some heavy angle on CC side of FB to weld wheels to. Center the weight up. I push my 250 LP tank around the garage when using.