"Thanks for all the input. The driveway, 500 feet, is asphalt, and I have a contract to plow it with a pickup. This is for the 500 foot gravel driveway to the barn, and paths up the hill to the manure pile, perhaps 1500 feet."
If I were you...
I'd drill a series of holes in the lower edge of the blade and attach a length of hard rubber (I've read of folks on TBN using some kind of horse stall matting, if I recall correctly) to the lower edge. If you can rotate your blade's mold board 180° (so the convex side is facing the direction of travel), do that. Then operate the tractor in a forward gear with the rubber in contact with the asphalt drive.
For the gravel and paths, lift the blade an inch above the surface and, again, operate in a forward gear.
The matting would take all the wear and reduce the amount of gravel you pull.
The blade should be set at a 30° angle to the direction of travel.
I'd start clearing when the snow accumulation was about 8". Your tractor should handle that fairly easily. This depends on the snow, of course. A heavy wet snow may give you some grief if you wait any longer. That Kubota is a nice machine, but it's a bit light. What kind of tires do you have...and do you have chains?
That's what I'd do...