Out of curosity, why is it that your interested in mowing with a hyd. mower out front on a tractor, instead of a conventional 3pt hitch mower & what will you be mowing (fields, tall brush/clearing, cleaning fence row's, etc)
Interesting thread. I bought a FEL mounted, very heavy duty, skid-steer compatible, rotary cutter in 2011 along with a new-at-the-time MF2660 tractor. The cutter was a low-flow version CID 5ft with 5/8" thick bidirectional blades and capable of cutting about anything you can get it over top of. HOWEVER, the low-flow version of the CID cutter is said to need 14 to 20 gpm flow. The 17gpm flow of the tractor was NOT adequate at all. It was so easy to bog down on inch-thick material it was not really very useful. See enclosed photos. There is much to be learned from this experience.
It would be a great combo to run a bush hog in back and one of these FEL-mounted cutters in front. To answer the "Why?" question, these FEL mounted cutters can cut brush and unwanted growth from the top down in places you cannot get with the hog. Overhanging limbs, down over banks, up against hillsides, in tight places where you cannot otherwise reach, etc. It allows one to "clear a path" in front to be further cut/cleared by the hog in back. If you are cleaning up an old farm overgrown by autumn olives these SHOULD be great machines and a great combo. By using the FEL mounted unit you can avoid major effort necessary to mount one of the boom-arm cutters on the back which becomes mutually exclusive with your bush hog. Sad to report the front cutter was effectively useless. You need a lot more hydraulic flow than an 81 horse 17gpm tractor provides. I ended up trading the front cutter for a VMC (Orsi brand) rear boom cutter which is a big job to get on and off the tractor and precludes using the bush hog when it is on. I'd be glad to elaborate on pitfalls and benefits of the 3pt mounted VMC/Orsi cutter,maybe another thread.
Let me put aside the concerns about loader capacity, weight, etc. First, my 4-in-1 bucket weighs just over 1000lbs. and the front mower is no more than twice that. Tractors in the 70 hp and above classes will have no problem lifting and moving with these cutters. That is by far the LEAST of your problems. The manufacturers are in apoplectic fear of people trying aggressive mechanical combinations. Somehow the lawyers do not understand I am always responsible for me and they are not.
One surprise issue (which even many long-term dealers do not know) is that essentially all tractors under $50,000 have
"one-track-mind hydraulics." You cannot raise the FEL while your remote is turning an hydraulic motor. Among your remotes and your FEL,
ONE FUNCTION WORKS UNDER HYDRAULIC FORCE AT A TIME. What happens is that using one of the front cutters (even if you had adequate flow, which you don't) the minute you try to raise the cutter or change the angle of it the motor shuts off. Then the motor jerks back ON as soon as you stop changing the angle or stop lifting. This is berserk operational behavior which is not productive, very unnerving, and eventually harmful to the machinery I would think. One could pursue adding flow splitters and elaborate hydraulic flow manipulation devices at great expense but that is moot if you don't have enough flow in the first place.
Bottom line: You need an independent engine (crankshaft driven) or PTO driven hydraulic pump to power these cutters. Otherwise they are simply not practical on a farm tractor. They are much better for use with a skid steer.