ORIGINAL: DGUY
I put a ST 90 on my Big Stick 60. I wonder if it will require some ballast in the aft section? I have yet had time to finish it because of my work schedule but it doesn't need much.
Put an extender on the battey pack and tuck it aft of the wings to get the C.G. right.
There's ample space for the pack back there, along with a small mount.