The extra weight of the power window assy seems to exasperate the broken door hinge area issue… which is unfortunately somewhat common on Studebaker Avantis….
Personally, I would attempt repair of the original door.. I have done this job before.. The trick is to cut away the fiberglass area with the access holes to put your socket wrench through to access hinge- to-door bolts… Then make the actual repair by roughing up the fiberglass and adding a layer of fiberglass cloth over damaged area… To make repair ‘bulletproof’, rivet a piece of thin sheet metal over repaired area….(holes drilled in metal)…Then fiberglass the outer piece back on.