A different interesting argument is what type/brand of epoxy you should use. I like West Systems or EZ-Lam, and EZ-Lam has by far the best working time of anything I have tried. I *don't* recommend finishing epoxy, even though it's nice and thin - it gets too brittle and all the different types I tried self-heated to the point it cut the working time drastically.
Brett
I agree about the finish resin in bottles, it's not great. Have you tried the 206 WS slow hardener, Brett, or are you only using the 205 fast hardener? I don't care much for WS laminating resin but their G-flex epoxy in bottles is great for bonding.
The brand of laminating epoxy shouldn't have much effect on pot life. It's whether you get their fast or slow hardener, mixed in proper proportion, and ambient temp, and if you keep the mixed batch in the cup or not.
If you are in a hotter summer setting, you should measure, mix, then pour it out onto a paper plate, so it won't have the tendency to exotherm, AKA, "Go Off". Doing this one little trick makes a huge difference. Then roll on with a 3" x 1/8" nap foam roller, use your slotted card to remove the excess.
The same brand and epoxy and hardener used in the cold winter(maybe not in SoCal), might find you needing to warm the resin and catalyst before even mixing, and then leaving the mix in the cup a few minutes to start the chemical process (depending on if you're using fast or slow cure). Sometimes I use slow cure more in the summer if it is really hot in the shop and fast cure in the winter if its fairly cold. If it's super cold, an electric blanket over the wing cores help with the cure.
I have to wonder why people ever recommend using finish resin when they are clearly laminating parts. It's meant to be used when you need to sand it. Personally, I try to use epoxy so that I will never have to sand it, in general. Plus, if you are wrapping a wing joint with glass, you are clearly laminating the wood with glass, right? I'd say so.... Plastic 4mil sheet from the DIY store works well over the glass and resin back in the weighted beds.
I'm pretty comfortable saying that if the guys that only use 1:1 hobby epoxy bottles each bought a quart kit of EZ Lam or Pro Set epoxy, a gram scale to measure it on, fast and slow catalyst, and some cabosil, they would probably have it a long time and also use it all before it went bad, with far less waste than the bottles. You'll need a stack of paper Dixie cups from the drugstore, and you probably all have stir sticks.
It's so much more versatile, as well as much stronger, and the lower viscosity gains you a better fiber/epoxy ratio.
That's my two cents. The REAL epoxy is very worth the added initial investment and cheaper in the long run by far.