Congrats on the license thing, thats a wise move. A 72 wont serve you very well here. Most properties are smaller with lots of landscape. a 50ish mower is considered big. I wouldnt want to push anything here in the summer. Just sayin' You understand when you get here.
If you can get 35-40 a cut and get a lot of accts in close geographic area, that lets you knock out 10-25 cuts day, you'll do alright.
It wont happen with a walk behind though. Not in this heat.