I've just purchased my first external flash, the YN560 III.

Context: Macro work, Nikon D3200, Sigma 70mm. My subjects are generally fish, and occasionally reptiles. This is to give you an idea of what shutter speeds I will be using and how I need to bring out the color in my subjects.

My question: I'm torn about whether I need a YN-560TX or an RF-603. What do you recommend?

The only benefit I see of the YN560-TX is that it can control power and some other settings. But do you'll really think I need this for reptile and fish? However I do feel that the YN560-TX might be a better investment to get serious, in case I pick up a third flash and go pro.