If greatlakesskipper.com doesn't have it you will probably need to go to a local canvas shop. You could try a dealer but I bet a canvas shop would be cheaper. The dealer might be able to get you in touch with the place that made them for Four Winns, who could possibly have the templates to remake.
I had my entire enclosure remade 2 years ago and it came out fantastic. It was costly, sooo costly but worth it. I can actually see out my Isinglass now.
Keep in mind this is their busy season so call a few places and get multiple quotes. I called I think 5 places in the off season and only 3 called me back with a quote. All about the same price btw.