I have similar size and weight tractor and run a mounted woods DS96. And have been real appy with it so far. I can even mow with the loader off. But cant go up on the trailer forward unless I leave the loader on, but dont like too. So I back on. But while mowing, there is no concern because the 3PH isnt bearing any more weight than a semi-mounted would when the cutter is down.
I like full mounted but mainly for three reasons.....1. Loading it on the trailer is alot easier. 2. Ability to very quickly raise the cutter if I run over something that just dont sound right/ Stump, rock, etc. 3. Makes a great counterweight when needing to do some heavy FEL lifting.
But nothing wrong with semi-mount either. Just not my preference.
Are you looking new? or used? Why the HEAVY 3308? Are you clearing alot of brush? Or is this more for pasture maintenance? Because the 2003/2308 is a little lighter and would work well. The Woods, landpride, rhino all also make nice twin spindle units. But I was at the mercy of what I could find used for a reasonable price. But had no single brand in mind.