I think I know where JerryG is coming from on 48" vs 60". In lots of situations, I agree with his approach.
My take on this is that 95-99% of my brush hogging is in grass/brush much less difficult to to mow than the max. the cutter is rated for. ie, The cutter is capable of a lot more on a well matched tractor (bigger than my tractor), than what I put it through. Nearly all the time, being able to cut the wider swath is most efficient in my mind, because the job gets done faster, and usually the brush is not thick enough to put any inordinate strain on the tractor.
In the 1-5% of the time where the tractor might be pushed beyond it's HP capability, you can always take a higher pass, then a lower pass over the thick stuff (multiple passes like you do with your RFM), or just take a ~48" partial width pass with your 60" deck. That way you'd only be engaging as much brush as you would with a 48" deck. Just because you have a 60" deck doesn't mean you have to cut a full width of the heavy stuff on each pass.
For me, the inefficiency of multiple passes, or partial width passes happens infrequently enough that it is more than made up for by having the extra width, cutting through the lighter stuff that I usually encounter.
Even if the field you are cutting is quite thick, you can use the altered passes mentioned above to get through the first mowing. Then, for maintenence mowing, the field will have shorter growth to deal with, and the extra width of the 60" deck will be much appreciated to help you speed through the job.
OkieG
19 PTO hp, 60" brush hog
