I did exactly the same, new Plexiglas (or acrylic to use the generic term) in powder coated portlights
. I researched all the options and found this website and learned that this company comes highly recommended. Blog – Selectplastics
So I ended up using Dow 795 and the results were excellent. Four years and not a drip. I found an online construction supply company that sold me the 795 super cheap
. Also comes in a very wide range of colors if you want to match the hatch
frame, trim or even the settee cushions
NOTE: this stuff is really, really messy. Don't even open a tube within 100 yards of anything you don't want it to get on. Were disposable clothes and gloves. Tape everything on the frame or parts
you don't want covered with goop. Tape the edges of the joints so you can peel off the tape and leave a nice edge.