The easiest way to put a hunting edge on a Grizzly out of the pack would be to maintain the factory bevel. This would require the least amount of metal removal. If you can maintain and keep a flat file against a flat bevel, a good single cut bastard around 8-10inches would remove that few thousandths of steel fairly quick. When you reach the point that the bevel has reached the edge, you can use a smaller single cut bastard to develop and hone a very sharp edge. This takes more technique than muscle. Most get lost and are stuck in a revolving door chasing their tail. You can find quite a few tutorials archived that cover proper techniques.
If you wish to modify the Grizzly by reducing the bevel angle and changing its overall profile, this requires the most amount of metal removal. There are only a couple of choices of files available to do this effectively. Again, this requires technique to avoid much work.
Some by-pass hand files and use power equipment. Even if you go this route, you should learn to maintain the edge with a simple hand file as it is not practical to haul heavy power equipment out into the field when hunting.
Good Luck,
Daddy Bear