Bob, not sure how much real help I'm going to be. You can see my equipment listed in my sig.
As a general rule, for the ground around here, I typ recommend a min 5hp per ft of tiller width. Soil is not clay/gumbo. My RSB-1300 is just about right for my garden plot. Used it on to reseed the pasture a few yrs back and being late in summer and virgin soil so to speak, I didn't have enough weigh to do much good. On the garden the tiller cuts like butter. But MANY yrs ago on the same garden using a 6' tiller with a MF 165D (~50hp+) the load was almost too much for the tractor. Used a Bolens GT, ~15hp, with a 3' ft tiller for many yrs and had to make many passes to get the bed ready for planting.
If your tractor can pick up the tiller without difficulty and you take small enough bites you likely can get by with this set-up. For me it would be too slow. If this is going to be a garden plot, after a number of yrs and with soil amendments, this combo may work well for you.
Oh, have a fond spot in my heart for Sand Springs. My grandparents MANY yrs ago lived near Hale Station (days when street car track ran down Charles Page.), right off Charles Page and just a little E of Sand Springs.