If you are serious about running propane then find a mower that has a factory supported conversion. I was kinda interested in running propane and was looking at the JD quicktrack. The dealer said no one around here runs propane on any mower. That was enough info to make up my mind. I bought an Exmark staris. I think propane might be a good idea for a fleet at a golf course- not a solo operator show. I've read some of your post and know you are still working on your business model and my suggestion would be to start with a 36" gate crasher. Get some accounts and see where that gets you. I bought a 48" cut mower the start of my third year. If I would have bought a big mower my first year I would have ended up with a 60" mower that would have been way to big for the smaller properties I service.