Advice needed, Td 8mm off true

hI there, built my hatch the other day and it is definitely 100% square. The issue is my Td isn't!
At the top of the galley the gap on one side is about 8mm wider than the other. The hatch otherwise if fine with no spring back. The roof edge is what's off true
Despite the issue I'm still pleased considering I'm only 8mm off true, and I've just been using cheapo tools.
Anyway it's 8mm wider one side to the other where the hurricane hinge will go. I'm not sure what to do.
If I glue on a tapered bit of wood 8mm down to zero would this be enough. There would only be about 2 screws on the hinge which would need to go through the taper or near the original edge. I'd just be afraid of splitting the wood at the glued join. The solution doesn't need to be pretty as it'll be covered in Alu trim
I really don't want to rebuild the hatch as my funds are quickly running out at present, seems a shame as well when it's actually square and has no spring back
Any other ideas?
I'd kinda ruled out putting the extra taper on the hatch itself as I've already skinned it with plywood
At the top of the galley the gap on one side is about 8mm wider than the other. The hatch otherwise if fine with no spring back. The roof edge is what's off true
Despite the issue I'm still pleased considering I'm only 8mm off true, and I've just been using cheapo tools.
Anyway it's 8mm wider one side to the other where the hurricane hinge will go. I'm not sure what to do.
If I glue on a tapered bit of wood 8mm down to zero would this be enough. There would only be about 2 screws on the hinge which would need to go through the taper or near the original edge. I'd just be afraid of splitting the wood at the glued join. The solution doesn't need to be pretty as it'll be covered in Alu trim
I really don't want to rebuild the hatch as my funds are quickly running out at present, seems a shame as well when it's actually square and has no spring back
Any other ideas?
I'd kinda ruled out putting the extra taper on the hatch itself as I've already skinned it with plywood