Loaded Tire Pressure & Scalping ???

I would like to know what tire pressure you are running or would recommend, with loaded R-4'ds on a 1026R. I just went over my mower (60D) setup again and have it dialed right in with the settings in the book, but I am still getting more scalping/streaking than I would like to see on side hill mowing (<15 degree).

I believe that because I have no measurable tire pressure (<2 psi) in my loaded R-4s, ( it came that way) I am getting a lot of tire roll which is aggravating the scalping/streaking on the mowers lower side.

Thanks in advance.