I think that a 60 inch might be a bit much for clay. Don't overlook a 42" tiller. Most will offset a tad and take out one tire tread and that is all you really need to do. I really don't think that you can overtill your soil as long as you add organic matter to the soil every so often. Garden residue, cover crops , old hay/grass, leaves and just weeds. I've tilled the same plot for thirty years and I have excellent soil structure. I also don't think you can get a hard pan with our little tractors and our lightweight tillers. You do have regular soil lower than the tilled surface but that isn't hardpan and crops will go right through it. I have a large garden and I like to allot a 1/4 section of it each year for a cover crop such as buckwheat or red clover. Next year that is my garden area and I rotate it about every 4 years. I usually sow a winter cover crop also. That landpride sounds like a nice tiller. Don't fret about covering your tracks. Just lap it and you'll get a good garden. By the time the dog/kids/wife/you walk all over it you won't even notice tractor tread marks in the garden.