Here you go...
Went out to the boat and wrote down the dimensions while I was there. It's a complex opening with angles on both sides and canted inward so I hope you can decipher my measurements. Seems like you asking for the top & bottom board sizes for canvas so maybe this'll do, here goes...
Top hatch board slat:
30 7/8" across the top, (side to side)
28 3/4" across the bottom
6 1/2" tall
Bottom hatch board slat:
22 7/8" across the top
18 7/8" across the bottom
11 1/2" tall
Companionway opening dimensions(measuring the channel that the slats set in):
Port side channel= 34 3/4"
stbd side channel= 35 1/2"
the port side is angled outward about 5 degress from bottom to top.
the stbd side is about angled about 15 degrees outward
Bottom width is approx 12"
top width is approx32"
Good luck. Hope you have what you need. Michael