Hope its repairable.
Hard to say what may have been going on at 1k' or whether the tail fracture took place at height or because of the crash. I had a scratch built sailplane fold up flying level into a thermal/mini wind shear once. You should have dive tested for tuck lower down where you could see what was going on. Several dive tests each time picking up more speed and checking how well it responded to up elevator.
Here is something else to confuse the issue. A flat bottomed airfoil when sitting flat will have a degree or 2 of positive angle of attack. After looking at the picture of your plane [nice looking btw] I noticed that the reflex might be enough to give it a negative AoA. The motor in its current location could give it just enough pitch up to compensate for this while under power. Draw an imaginary line through the nose of the foil to the highest part of the reflexed TE and see if it is so. The decalage of the tail should be the same or up a degree.