I will agree with those that are saying that plowing with a lawn/garden tractor is a compromise at best. I've done it, not a good experience.
HOWEVER......I have a plow on my 20HP Gravely zero-turn that works awesome. I bought the mower and then picked up a plow as a temporary measure until I could get something else for snow plowing. That was in 2008, and I'm still using it, because it works very well.
The primary difference/advantage is that all the weight, including my fat ***, is directly over the drive wheels, which I have chains on. The plow is 50" wide and over a foot tall and I can pretty easily run the first pass through snow that is rolling over the top of the blade. A couple times I've had a bit of trouble with really wet/heavy snows, but only the first pass through, and then it does fine pushing the remainder back.
I adapted a 38" blower to the same machine, and while it worked well, it actually took considerably longer to clear the same area. I used it one winter and haven't used it again.