Gillie - there's nothing structural in that splashwell; it's about 1/8" thick FG. I think Armstrong may have some hatches that they use for their brackets; the Hermco bracket uses a couple of the small round Armstrong hatches for internal access to flotation tank.
I actually made my own hatch; just put some 1" wide chrome brass trim with screws on one side around the piece of FG I cut out, and glued some 1/2" thick foam gasket material on underside of the trim piece that stuck out over edge of FG. Mounted some half round buttons on some 1/4" teak at the 4 corners of the hatch; then just compress gasket and rotate button over the trim piece to hold it down. Not as fancy as store bought hatch, but it worked and was watertight; just had to replace the gasket periodically, as it wasn't very durable. I added the oil tank to that space when I repowered. Have a slide show in photobucket that shows the old hatch hold-down scheme and same area after splashwell was cut away, as well as baitwell and top mods. Will see if I can post link to it here.
web page You can click on the picture to stop slide show to look at details.
Regarding the top set up, any good canvas shop should be able to duplicate it. If you use original mount point for frame, it will fold down in front of windshield like original; you can also brace it off side of windshield as shown in an earlier post. This is important because bimini tops are notoriously "un-stiff" laterally! If you mount sun top on a track, when folded up it can lay down on top of windshield if bimini is down. If bimini is up, you can use the straps to tie folded sun top to bimini or slide back and lay it on transom. I wanted a large bimini that came forward of windshield so I have plenty of shade from all directions from about 9 am to 3 pm. We put the zipper for attaching the forward clear windshield-to-top filler about 18" aft of front frame, so the clear piece has same slope as windshield. Side curtains attach to front filler with velcro so it's relatively water tight.
The "Unohu" belonged to my friend Bob that bought it new from Carl Moesly; it was the display model in the 1965 Miami Boat show! At the time of that photo he was on his 3rd of 4 engines he wore out in that boat - he went diving almost every weekend, 12 months/year in addition to a couple of annual Bahama trips! Check the "Proud Owners" section on Carla's
www.moeslyseacraft.com web site for more info on it.