Gws A-10...speed 400 Pusher?
A single spd 400 in the tail should work great, and should be of good speed with a zagi prop. Maybe use a 6V motor and an 8 cell pack. A 8 cell he1100 pack will fit into the battery slot provided if fashioned as 5 standing up and 3 laying on top of those. You may need a few mods to for strength like the fuse mounted wing nut being a weak area for your weight, also maybe a few bamboo spars in the fuse, it's fragile at 16 oz.