With my little guy (he was small enough to fit into a "shoebox" tub when I got him) I drilled a hole in the tub and installed a wooden bird perch. I also gave him a branch that I could remove. Some of the best perches I've seen were pieces of pvc connected to form a lattice (think window pane seperators) that were laid in the tub so that you could pick up the perch with the snake on it.

Mine was very skittish at first and wouldn't release his perch when I had to remove him, so I prefer using the removable ones.

If you can make something out of pvc with multiple "branches" on it, I think that will be fine. I was able to just lean mine on top of his hide box to give it height, but if you are getting a larger jcp, this might not work for you.