I used this company.
http://www.wynneinc.com/
Don't bother looking any where else. I've done the reserch. They are the only marine window company that post's any price's on the web.
They build a fine product.
Their window's have a trim ring that is installed on the inside. The screw's go thru the trim ring and into the outside frame. No fastner's screw into the boat.
I highly recommend that you make the template's that you send them with the 3in radius in the corner's. It look's MUCH better and is stronger than square corner's.
Before you do the final install. Coat the stainless screw's with Teff Gell.
http://wolfwire.com/tefgel/Tef-Gel.htm
This will keep the discimler metal's from reacting to one another.
Mine are the Black frames with Laminated Safety glass and Solar Gray tint.
I also recommend that you make the front window hinge open.