There is no reason to make the setup more complicated than it needs to be. The numbers are fine so why add on more expense and possibility to have a issue.
If more heat is ever needed a heat lamp suspended on a lamp stand will work great with a tub. I kept a big blood python this way while waiting on pvc cages I ordered that took forever. You can actually create a nice hotspot and heat gradient with a lamp alone if needed. Its just important to suspend the lamp so the tub is not melted. I also used this method on young bloods when they were in quarantine. You can use a dimmer to adjust the heat or do as I did and just figure out what distance from the tub gives the proper numbers and lock it in there. That is how I adjust all my lamps. I use them for my ball, hoggy, and pacman.