your mount is a LOT different than those Charles,, from experience,, I do note expect yours to survive,, there is a lot more torque on there than you think,, and with no web to tie the attach points together,, It wont take long to fatigue and fracture that plywood,,
however,, its your airplane,, and as I have said, it wont matter until it does,, the sad part is that repairing it will be catastrophic to the airframe finish,, if you fly it,, and it survives first flight issues,,
have you done a preliminary weight and balance on it yet?