I think the main thing is keep your bucket cold, same temperature as outside. I've noticed in my years of doing snow removal, it is when I come out of a heated garage is when the snow tends to stick to my bucket... Also keep in mind that it also depends on the type of snow that you get. Sometimes snow is wet and sticky... then you kind of have to bang your bucket out...
I know people try "Pam Cooking Spray"... but I think overall that is very impractical.. It will take a full can of Pam to coat the inside of your bucket, and how long does it last? Every time you dump you take a little Pam with it...
I don't know, maybe car wax might help... but then again I don't think each application will last very long...
Just my thoughts.... for doing a long driveway for a long winter, I think you would be much better off with either a blower, (Front or Rear) or a blade (Front or Rear)...
The combination I use on my machine is the front loader with bucket, because I need to do a lot of peeling packed snow out of a busy parking lot, and I use a 74" Rear Blower to do everything else... it works good for me....