Yeah, 1 to 4" sounds fine by me - can't see why you'd want grass lower or higher than that.
Looks interesting, and Caroni seems to build decent, but not perfect stuff - ie you more or less get what you pay for.
I'd be more likely to get the 71 for a lawn, but for your purposes, its probably fine. Though wouldn't a flail mower be better in some ways?
Frankly, I think you should get this and review it for us!