First off, the tub is way too big for a juvenile and you would have to fill it with so much stuff to make the baby feel secure, I would go for a 6 qt or 12 qt and just wait untill he gets bigger. Also you can find latch top 15 qt tubs that you could use, since i know the 34 qt are the lime green handled latch top ones, and the 15 would be perfect for now.

As far as flexwatt is concerned PLEASE use a thermomstat, NOT a dimmer for flexwatt and really watch it closely. Flexwatt gets VERY hot and if left without any heat control, your snakes are going to be sweating out at like 130 degrees! But depending on the tub you get, i would only get the 3 inch flexwatt or the 4 inch from Reptile Basics. The 11 inch is just too big and would cover way too much of the tub and wouldn't give your snake enough room to have a thermogradient.