I think its best to keep the blade as close as possible to eliminate as much leverage on the machine, get it to far out and it will be a bear to operate. Gravely used a heavy blade on the walkers, its 48 wide and 1/4 thick steel (read farkin HEAVY) and thats to keep it down on the ground using an L model, you want to put a tin blade on a 12 Kohler (Kohler machines usually had an additional weight bolted between the plow and hitch for even more counter weight),,,,, get some weight on the blade to offset the Kohler engine or you will be walking and lifting the handlebars (uncomfortable) to keep the plow on the ground. Gravely walker blades seem to approach the snow at a different angle than most blades I have used, the blade itself has a sharper arc and its positioned sort of to get under and roll the snow rather than the more common flatter arc of a normal 4 wheel tractor blade. Save yourself the time and work and just get the right blade I think you will be much happier, they usually can be had for a hundy or less. Im not saying your idea wont work, it will but I think you will find the right blade will have more capacity and just plain work better.