Lots of Research .....................
should I get directly from Hunter or will any of the advertised low profile hatches serve just as well.
.................. is the first item on your "to do" list.
1. Hunter uses (used) many different makes of hatches over the years. What's yours ?
2. Is your size still available from the manufacturer. Check their web site.
3. Not sure exactly what you're replacing ............ if you're starting from the frame which is attached to the deck, does your cut out match a new unit ? A close but very slightly smaller unit is a monumental challenge. Web site.
4. If you're only looking for replacement parts, does the manufacturer supply them. Web site. Your hatches are a few years old.
Once you have this info, Hunter Marlowe parts (this web site) may be able to supply the pieces and parts you need.
Prior to the web, I don't see how one could ever do a project like yours.
Good luck and let us know how it went.