It seems to me like its going to be expensive and a lot of aggro, there must be an off the shelf product that will do the job?
6x4 tractor traction when running light is just plain rubbish, even an empty 8x4 tipper can get tail happy.
We used to look after a couple of 6x4 tractors and if you didnt get a little run up they would cross axle on the slight abrupt incline just getting out of the yard and that was on concrete!