If you have the mowing to justify a 90" RFM, I'd keep it.
I'd written I had 2 Befco mowers. The first was a 60" unit that came with the Deere 670 I bought 10 years ago. It was a great mower. I kept it when I traded up to a Deere 790 and used it another 5-6 years. I traded the 790 and mower for a Deere 4400 which came with an 84" Befco. This is also a great mower but just too darn much for the acre of finished lawn I mow. The problem isn't so much the overkill for the mowing...the mower is on the edge of being too big to get into the garage (about 1" clearance each side) and I had to store it outside for the winter as it's wider then the door of my outbuilding.
Frankly, I'd like a 72" mower...that size would fit best for my needs.
BTW, that 84" mower weighs in at just under 800 lbs. My 4400's hitch is good for 2200 lbs 24" aft of the links. I've lifted and transported it without the bucket on the loader, but I haven't dropped the loader off the tractor yet. I'm pretty sure I'd want a few front weights if I transported with the loder off.