I had the same problem with my hatches. I went with a simpler approach - try warming the hatch covers (I used a halogen lamp or a lightbulb) enough that the epoxy softens a bit. Then strap them in place (with band clamps, etc.), at the right curve to match the deck. After a few days of curing, remove the straps and voile'! they should stay. I repeated this a few times until my hatch covers were convinced I was serious. It's a non-invasive and easy thing to try. Maybe it will work with yours.

Good luck,

Mike