Worst part about hardtops is also the best part. Very watertight, also very wind-tight. They can get very hot. Think about having good quality overhead hatches, at least one, or preferably one over each seat. Side sliding windows? Very expensive, you may be better off with a hardtop and clears on the sides with a zip-out section. Don't go overboard with overhangs--in the event of taking solid green water, it is much better if it can run up and over--if it has weight and velocity, and gets under an overhang, it can do damage. Putting your e=windows more vertical also has the positive effect of reducing sun intrusion into the cab.

Make sure you have enough headroom at the front if yu have to stand and drive.

 Thanks heaps for the ideas. At the moment it’s all solid windows so no exactly what you mean about heat. I’m a glazier so was kind of hoping to keep costs down a little for window profiles. Am I best off with glass windows or polycarbonate. Didn’t even think about that with the hardtop overhang. Once again thanks heaps

 Lexan scratches up easily, as you would know. But certainly a lot cheaper than tempered glass. Looks like an ali boat?  That gives you plenty of options re the shape and construction. 

 Yes I know what you mean. I can get toughened Glass at cost so may be an option. Yes plate alloy boat been looking at different designs but hard to know what would look good

Can also go laminated glass as well. Either as a rubber fit or glued into a frame, just run some primer around the edge of the glass beforehand or else it will start to delaminate down the track