Ok, a bit of an inadvertant up date. Had the tank off the bike today to do some details before painting. Story short I knocked it off a shelf and it had abot a 5' fall to the floor. And of course it landed on the very point of the angle cut. Hit with such force it gently folded the aluminum end plate outward until it broke its bond. Strangely the PVC was not hurt, it just flexed. What I got besides a repair job was a chance to see the inside of the tank and how the bonding had done. All the materials, PVC and the JB Weld were in fine shape, no adverse affect from the fuel. In fact the bond was so good that as the plate separtated it pulled a layer of PVC away from the tank. Trust me JB is hard to remove. Had to sand the tank, and heat the end plate with a torch and scrape it with a razor blade. So the short is looks like this is a viable way to build a tank.
One last thought, since the PVC is so flexible perhaps bonding would be better with a 3M product for boats. It is a polyurethane bonding agent that is incredibly strong, should be fuel proof. Thing is it remains somewhat flexible over its life. This is probably the glue for this type of tank. You cant believe how strong this stuff is!