I used a 4 foot tiller behind a JD sub-compact 2210, listed as having 23 HP. Needed to be run in 4wd and needed the frontend loader on to counteract the weight of the tiller. Granted, this 2210 is pretty much just an oversized lawn tractor in my opinion, and your tractor is larger, so you shouldn't have problems handling a 6 foot tiller.
