The biggest problem with belly mowers(which I absolutely hate anyway) is the fact that the mower discharge guard is not your or yours shrubs freind and the guage wheels will cause you many problems(especially in our case of mowing 5+ acres every week.
The poor quality of cut and turf condition after mowing versus the flail mower with good grass knives and tires if it is trailed unit (like ours) is another huge issue with me especially with good turf.
I would strongly suggest that you invest in a rear mount 48 inch Caroni finish mower for your tractor IMO, and you will never want a belly mower after you see how nice the lawn looks after you mow with it, and it is a much safer mower to use and you never have to clean it after every mowing as the flail mower does not muck up like a belly mower.
The hydrostatic transmission will allow you to easily trim with the rear mounted flail mower with some practice, and it will become second nature to you(mowing wet grass is breeze too) and you have little to no clippings to deal with, and if the lawn gets a bit long you can simply go over it again and shred them some more and they will be gone, this never happens with a belly mower unless the grass is powder dry and a flail mower will shred the leaves rather than blow them around like belly mower does.
The flail mower will not scalp like a belly mower either as the rear roller is the height gauge on the caroni and other brands of flail mowers.
The flail mower is better as it does not tear the grass blade like the rotary belly mower and the grass is much less stressed than when using a belly mower as the amount of grass blade sliced at each mowing is tiny compared to a rotary mower blade and the flail mower will not turn anything the knives hit into missiles injuring or killing a pedestrian or a pet in the yard.
The folks at
Agri Supply - Farm Supplies, Tools, Lawn Mower Blades, Cast Iron Cookware have a Caroni flail mower internet sale price with shipping to your door included in the price.
I neglected to add that you can purchase a Hydraulic shift kit for the flail mower to allow you to mow closely to many areas without smacking the flail mower or the tractor-very handy with the R.O.P.S. as tree branches are very nasty when bent back and you forget to duck or move away when pre occupied with watching the mower guard of a belly mower.