Pros on a 6ft I do not have something on the back of the tractor that is wider than the tractor. If the tractor can fit through, so will the mower and I do not need to keep reminding myself it is back there. I go in the same tire tracks on the next pass, so in my case I would cut more grass in the same time. Less grass matted down from the tires. All my garages are 9 foot wide. While 7 is smaller then 9, backing in with a 6 foot mower is an easier, then 7 foot. I rarely need ballast on the back, but when I do I use my mower as it weighs 700 pounds, again I do not need as much to remind myself it is back there. Easier to move around, when off the tractor.
Pros on a 7ft You are going to do a better job of picking up the grass that the tires pushed down.
If you are looking to speed up your mowing time. Instead of backing up for some reason, I just go around in a circle. It is easier on me, the tractor, mower and the grass.
