With a heavy jabo, 50% gas and auto take off you "probably" will not clear the building ie, a 47D-40. A P-51D with big bombs and rockets, 50% gas will not make it with WEP and flaps every time, seems you have a 50/50 shot.
I've watched 262's not make it.... 3 different pilots in fact.
So the OP does have a "bit" of a gripe, so there is that
HiTec is aware of it, but it's not really an easy fix. Read that a couple weeks ago. Maybe it time the shed will disappear.