You are comparing the light duty batwing with their medium duty mower.
If that was in reply to my post, all models I referenced are batwings.
I agree that the lighter weight batwing, such as my RC2512, would not be the choice for mowing brush and saplings. I mostly use mine for mowing my CRP fields. I cut them in July and September. There is some brush but it is small. The mower does an excellent job...for my purposes. It also does a wonderful job in our front yard and fields. Flex-wing mowers tend to scalp less.
I have an RCR 2672 mower (6', not batwing, 3" cutting capacity). I have used it for cutting a lot of brush and saplings. With my
L5740 I have to go very slowly to cut brush and saplings with that mower. I seriously doubt that tractor would be able to handle much more cutting width. I also doubt the
M7060 would handle brush and saplings with a batwing.
Absent a very large tractor (100+ HP?), I'd not think tackling brush and saplings with more than a 7' mower would be a good idea.
But, if someone has the HP for it, would be a lot of fun.
There would only be two reasons I'd consider a lighter mower over a heavier one:
1 - Weight - Can my tractor handle it?
2 - Cost
When I bought my wing mower, the initial plan was to get a
M5-111 and a 15' wing mower. It was to replace a JD tractor that was mostly used to run a 10' offset (semi mount) Bush Hog mower. I already had the
L5740. The
L5740 is just under the size required for the 10' mower. It runs the 6' mower just fine.
In researching, I realized the
L5740 would run the RC2512 and RC2515 wing mowers (perhaps due to their light weight?). I felt the thick CRP would not be a good fit for the
L5740 and a 15' mower. The fields have a bit of hog damage so we have to go slowly anyway. The
L5740 might as well be cutting 12' as 6' per pass.
It also works well on the
M7060.
I also thought that running a 12' mower behind one machine and a 10' mower behind the other was preferable to a 15' on one and a 6' on the other. Ok, perhaps that is a wash.
So, I went with a lighter wing mower for versatility. For my situation, it worked out very well.
Good luck with whatever you choose.