Hey Hoss - I feel your pain. My club's grass field was completed in a rush, so it has lumps and ruts. It has been rolled numerous times and does seem to be slowly improving. Keeping it mowed also helps a lot - my field is mowed 2 times a week.

A lot depends on what size/type jets you plan on flying. You need 2.5" wheels or larger in my opinion. My Kingcat handled the field pretty good, but smooth landings are the key. Jets with knee struts (at least on the nose) work the best. Look how popular Jet-1A stuts are in Europe - also Robart now has trailing struts. You could just get a big L-39 & have no worries - those have truck suspension.

However smooth the grass, you'll still have people complaining about your burn spots - but that's whole other problem