When I built my level 1 Graduator, I used 100% RAKA epoxy. https://www.raka.com
Their epoxy is meant for boat building. It's a great fiberglassing epoxy. The 2:1 mix is easy to use.
It's like buying epoxy from Costco or Sam's Club. You pay more up front, but you get great big containers and the cost per serving is lower.
At first I used ketchup/mustard dispencers that you can buy at a grocery store for the resin and hardener. I used small measuring spoons to measure.
Now I have a pair of pump lotion dispencers that I got from Target or Wallmart. I figure if it can pump hand lotion, it can pump epoxy resin and I was right.
For attaching things to other things, I used filler to thicken the epoxy. Maple flour works great and is cheap. I thickened to peanut butter consistency for attaching stuff, mayonaise for fillets, unfilled for laying up fiberglass. Made for a very strong rocket because the thin epoxy penetrated well.
OTOH, it took forevery to build that rocket because it took hours for the epoxy to set up. I'd put on one fin a day.
That Graduator is still flying. It's survived a forward closure failure, a number of flat spin recoveries and a few hard landings on the Bonneville Salt Flats (like landing on concrete). I'm going back to that technique with my Level 3 rocket. I think that this boat building epoxy is superior in strength and flexibility to anything you can buy in the hobby store and ouce for ounce, it's cheaper. I can get 1 1/2 gallons (192 oz) for $76.00. So, I it's costing me $3.56 for 9 oz of epoxy, which is about 1/2 price for the hobby store stuff.
For speed, though, I'll still use the 5 minute Bob Smith epoxy.