if you are going to swing the wings back than most of the weight is twards the back. So account for that. I would take and weigh the plane at the rear wheel with the wings pulled back and weigh the mains, you'll get your answere. one last thing, don't support from the tail feathers, this area can't take the load, you'll have to support from the wing and tail(fuse) together I would think, just remember it's pretty heavy back there with the wings swinging back.