I just finished my work week - got home five minutes ago so the next four days I'm off and if it's not too cold will be working on the fiberglass. No photos yet but haven't touched it since putting on the first piece.

That resin you linked should be fine but before using it on anything important, glass a small piece of balsa about 3" x 6" and see how long you can work with the resin before it starts setting up. If you really get a good 20 minutes of working time it's fine.

The stuff I use is 30 minute but it can really be worked for well over an hour. I like it but it is slow to set up. I originally bought the 60 minute but it took WAY long to set up and most of it soaked into the wood which is bad. So I got the 30 minute and like it. But I'd like it better if it were a little bit faster. All of their resins work way longer than stated so I'd get 15 minute if they had it and if it were consistent with their other resins I'd probably have over 45 minutes working time. Only need realistically 15 minutes tops for anything I've ever done. After that you just wait for it to cure.

http://www.acpsales.com/EZ-Lam-Epoxy.html

Don't sand too soon. If they excess resin on the cloth is rubbery then it is too soon. If you bend it and it breaks clean then it's ready. You want the resin hard for it to sand well.

You can use polyester that you have if you want. I just think it's really nasty to work with but it's been used to apply glass for decades so it works.