Baby steps are fine, but 72Mhz seems like an unnecessary (and therefore expensive) step to me.
Mach, if I were you, I'd fly LOS first for quite a while to get very comfortable with your wing. Then add simple FPV gear, and keep flying within LOS range with a spotter a few times. That way if you're in trouble you can look away from the screen and have your spotter show you where the plane is, LOS (or even take over, if you have a buddy cord). Also, if you go down, you're close.
Then, once you're comfortable flying FPV, buy the UHF long-range system, which is what you'll want to end up with anyway. That doesn't mean you need to take it to it's full range the first day. You'll probably go a little further each time, learning how it does. The range will be there when you need it.
See? No need for a whole new 72Mhz system, and the money it costs. The Spektrum you've got will do just fine up to the point you're ready and comfortable with long-range.
...all this is exactly what I'm doing right now, only with a Turnigy 9X until I have the extra cash for UHF