I have a Yanmar 1303 tiller and use it behind my S650G. The tiller does sit tighter to the rear of the tractor (and therefore the rear tires) than my other implements, but as long as I keep my sway chains adjusted it does not hit. I don't know specifically whether the 790 would be similar and the various Yanmar models might vary in configuration. As far as I know, there is no need to use the special Yanmar toplink as they are actually made to work with the Yanmar tractors, not necessarily others. You will need a short toplink though. Probably in the 8"-12" long area. The pto shaft also usually needs shortened. I find the close fit an advantage for 2 reasons: 1) easier to maneuver in tight spots and 2) less lever arm on the tiller = fewer times the front wheels leave the ground.