I would guess that you are streaching it a little. I have a 2210 that I use a 50" tiller on. I have no trouble with it. My garden has been worked and tilled for 40 years. it works good. 50" is the largest recommended by Land Pride for my 17 PTO horse power.
My 2210 has a 52" tiller that weighs about 400 lbs. It works great but I don't think I would want anything bigger. I usually keep the FEL on for better steering and traction.
I too have a 2210. I run a 48" inch tiller and I can't imagine anything much bigger on my tractor. 50 or 52 I'm sure would be OK but 58" would be awfully big.