Catman, I've been following since recognizing that our tractors and tillers are so similar. My toughest performance test was tilling a 30' x 30' patch of lawn in heavy for the area soil into a 'garden' for a Sis. (
her way, of course

)
I set the skids high up, maybe skipping a bolt hole or so, and my 60" KK (weight unknown) went nearly full depth on the first (creeping) pass. Went crosswise to that once, then a third pass like the first. There was no grass or weed matter to rake off by then and I suspect we got an honest 6" of plantable depth. There's a routine at the end of a row. I declutch, disengage PTO, lower rpm, raise 3PH, turn, lower, raise rpm, clutch, engage PTO and take off. ... Why I mention this is the bigger laugh you'd get watching me
do them in order than my trying to look clever writing it down. :laughing: (lotta shakin' & noise, sometimes)
An interesting sideline to that task was when I complained for the sake of my gadget about splitting nearly fist-sized granite rocks and asked onlookers to grab a few between passes and she chewed my six for days about 'rocks' as if she'd wanted more brought in. Of course to get even I neglected to mention for a season or two that when hubby's pulling weeds (w/seeds set) in the fall they shouldn't be tossed into the middle to be tilled in later.

(
his way

)
Anyway, what I came away with there and since is: - that on a first pass one needn't work too deep, easier yet if the area is flat or you're good on the draft control, - that on any subsequent pass, the tiller might surge & bounce within play in the pins etc as on the first, - that HST is the trick, you creep forward as the tiller works to depth under whatever weight it does have, - and what was most important to me that 540 RPM just didn't work for me on any job yet.
That 'shakin & noise' I get when lifting the tiller w/o disengaging first shouldn't also be there when it's working the ground and the PTO shaft isn't at any odd angle. I suggest you consider reducing rpm as much as say 10% by trial & error, but based again on our tractor & tiller sizes being so similar. My NH's rpm for 540 PTO speed is 2450, but tiller works best around 2100-2200. There'll be a setting where things just seem to run their smoothest, and I'll bet you find it in a jif.
Glad to have you with us. t o g