Might look at Hustler Fastrac SDX. Can get Kawasaki FX730, Hydrogear 3400's and 54 or 61 inch cuts and suspension seat. I wanted the Patriot, but they went to self contained reservoirs on the 3400's and I want separate reservoirs that I can see and fill with worrying about contamination from...
My experience with tubes in a zero turn has been less than stellar. Too much sheer between tire and tube, especially on left side tire. A tube will get you going again for a while, but not a long term fix for this application.