Dunno about green goop, I use el-cheapo 2-part-poxy with no problems. And if you make the toobs too short the fuel does indeed flow over whenever you hit a pothole. The road builders around here are particularly skilled at bumps and potholes, so I'm gunna pull the carbs and make up some longer toobs. Since those Wallies won't fix the roads.
Made up a steel sleve out of a 2 inch piece of Falcon fuel line and use that as a sort of a "crimp tool" and put it over the toob and beat it with a hammer. That basically "crimps" the toob in the hole and it doesn't move. Sort of like a press fit if you don't have a press.
No doubt SISF has a better jig for doing it, and yawl should just send your carb bowls to him.