RE: .21 Zippkit ready to go
Do not use Ca around foam .It will eat it. 30 min epoxy & 5 min epoxy If & when you use 5 min you will need to cover over it with a sealer / 30 min CA & a squirt of accelerator is good for the 1/4 balsa angle , as well side ribs
5min & nitro are a No No = strength, good
30 min & nitro is ok = strength ,best
As far as a fuel tank the prints say Sullivan SS -8 OZ PACKING NOODLES TO HOLD In