galley hatch help...

I am nearly ready to mount my rear hatch and need some advice. I went with my own design and have stumped myself with a couple of problems. I went with a split opening lower door + upper hatch (so I have three doors in all). The split lower doors close and interlock and I plan to do the same on the upper hatch.
here is my question... the top edge of the split bottom doors is a flat surface that is perpendicular to the ground. The top hatch comes down but it's bottom surface is at an angle that doesn't match the top edge of the split doors. If I am guessing - the bottom of the hatch is about 20 degrees off from the top of the split doors. I need these to match up so that they will lock up and seal properly.
Does anyone have a suggestion on how I should measure, mark and cut where these doors meet? I am thinking I would rather cut the matching angle on the lower split doors since they are flat and easier to manipulate + if I messed something up these would be easier to fix/do over.
Right now I am leaning towards measuring/marking the angle of the top hatch and then cutting that angle into the top edge of the split doors with them both screwed to a sheet of plywood and lined up perfectly. I think if I cut them separately they might not match.
When I framed up the upper hatch everything fit like a glove and the angles matched. Twice now when I have skinned it something happens. You can see in this pic how things matched up when it was just framed:

The first attempt was a disaster. I skinned the inside and outside with the hatch on the ground. I think that my weight applied to the ply to bend it deformed the frame. I then pulled off all of the ply, scraped and sanded off all of the PL Premium
and reinstalled the frame only. I still fit perfectly. On my second attempt I skinned the hatch with it in place and it turned out much better - but still not perfect for some reason. At this point I don't have the hinge yet so maybe when I hinge it on things will fit better...
here is my question... the top edge of the split bottom doors is a flat surface that is perpendicular to the ground. The top hatch comes down but it's bottom surface is at an angle that doesn't match the top edge of the split doors. If I am guessing - the bottom of the hatch is about 20 degrees off from the top of the split doors. I need these to match up so that they will lock up and seal properly.
Does anyone have a suggestion on how I should measure, mark and cut where these doors meet? I am thinking I would rather cut the matching angle on the lower split doors since they are flat and easier to manipulate + if I messed something up these would be easier to fix/do over.
Right now I am leaning towards measuring/marking the angle of the top hatch and then cutting that angle into the top edge of the split doors with them both screwed to a sheet of plywood and lined up perfectly. I think if I cut them separately they might not match.
When I framed up the upper hatch everything fit like a glove and the angles matched. Twice now when I have skinned it something happens. You can see in this pic how things matched up when it was just framed:
The first attempt was a disaster. I skinned the inside and outside with the hatch on the ground. I think that my weight applied to the ply to bend it deformed the frame. I then pulled off all of the ply, scraped and sanded off all of the PL Premium
