Door warpage: It sounds like you have encountered a door fit problem which we have encountered on many Glastars as well. What we have come to realize is that after the hulls and fuselage have been mated to the wings and the doors preliminarily fit and hinges installed that the doors do not conform exactly to the contour of the hull. In particular as you had noted, the top aft corner of the door on almost every airplane that we have installed doors on needs to be re shaped in order to make contact with the hull in the right sequence for the latching mechanism to work properly. Another problem area is the lower portion of the door where it makes contact with the lower sill, this area of the door seems to have too much curvature to match with the hull.
Some of these adjustments can be accomplished by spacing against the cage tabs, however when the door is grossly mishaped this will not remedy the situation.
Solution: re shape the door prior to installing glass so that it makes contact with the hull and is fare along all edges. This is easier said than done as we have spent more hours than I would like too in this process. The primary tool is heat. We use several hot air guns being careful not to overheat the laminate as this will destroy the integrity of the glass. Also we have made small ovens when it becomes necessary to heat the entire lower panel of the door.
Door latch fit: We have encountered difficulties with installing door latch mechanism #101-16003-11. This is the door latch which has a stainless steel shaft welded to it. We have had problems with 4 different airplanes where the shaft will not fit within the bushing which is bedded into the hull in step #27 fuselage assembly bushing # NAS 77 A5-062. The stainless steel shaft is evidently .011 oversized. If your bushings are already installed this makes it difficult to enlarge the hole as you will need an expandable reamer preferably. Someone has suggested using a drill bit for this enlargement however I think this would be unsatisfactory.
If you haven’t installed the bushings into the hull as yet, I would suggest checking the fit and if the shaft is oversized have the bushings reamed at a machine shop. This should save you headaches down the road.