As far as downward pressure, it would just be nice for the rototiller when it is reluctant to start digging.
I was all set to put fluid in the tires, and then I started getting talked out of it. The local JD dealer said he had a tractor in for getting thawed since the low temp ww fluid froze. Shouldn't happen, but it did.
I also mow a lot in the summer on some steep hills. I wonder if the extra weight will mean that I can't hold my normal gear up the hills. I wouldn't like that.
I also see that the manual calls for 21.5L-16.1 rear turf tires. Mine are 44X18X20's, which I would say are wider by a good amount. I'm sure that doesn't help in the snow where you want some pressure on the surface for traction. I called JD, and 440# of wheel weights are $1,300! I have a bunch of lead laying around in pig form, but I haven't found a good way to mount it usefully.
I was looking at the lane today, and come summer I will move the lane a bit so that it isn't the low point. I have no where to put the snow right now and it just fills up when it blows, which does indeed blow. Front chains are still an option, but I also need to get the rear to contribute. Keep the suggestions coming.