Welcome to the forums!
Radiased/rounded edges will be yer friend...especially at the front/nose of the camper.
Don't fergit to allow enough of a gap between the camper and the vehicle fer the times the frame flexes and the gap closes...especially at the top. You wouldn't want to find out that yer camper nose gits cracked or sheered off if it contacts the vehicle, right?
Keep in mind that yer gonna have to make decisions on what to compromise on so yer camper best fits yer needs.
Is there gonna be any kind of frame to keep everything tied together or are you gonna depend on the corner joints to be able to withstand the road forces? A frame would be highly recommended fer the top as it will encounter severe forces that will easily peel the FRP or foam right off the camper.
Have you inspected the other commercial camper tops up close and personal fer any ideas fer yer build? Does the top expand/raise up fer extra headroom when yer parked?
Mechanical latches that keep the top securely locked in place are a good idea.
I'm guessing yer measurements are in centimeters? So 1 cm is about .394 inches.