I use the alcohol too. makes it nice and thin so you can paint it on the firewall and coat the inside of the fuselage where the tank goes. It's also good to "epoxy paint" joints in the fuse/wing that you want to strengthen without adding a lot of wait.

And definately protect the threads of your t-nut from the epoxy. trick that works real well for me is to drip candle wax into the threads. this will keep the epoxy out, and you can either drive the wax out with your bolt or heat it and it will flow out.

My 2 pennies worth