I used to turn lots of bowls. LOTS of bowls! When I turned a green bowl blank, I kept it to about 1" in thickness, coat the end grains with preservative wax, and put it in a paper bag. Then it sits on a shelf for a year at LEAST.
In my humble opinion, its best not to rush the drying of a burl or any other wood for that matter. Checking and cracking can pop at any time during the drying process as it is, let alone inducing any artificial means. I tried the PEG thing. It makes the wood a little funny, IMO. Nothing better than naturally dried wood, and the grain seems to be nicer. Maybe my perception? Seems to me, that in making handle materials for knives, the wood would take maybe 6 months or so to dry fully.
The general rule have always been: One year drying time per inch of thickness. If you take a burl and slab it up, it'll dry to a usuable moisture content in only a few months, especially if its kept in a dry house... like under the bed! Don't laugh. I did this. Made a hell of a mold under there and really ticked off the Missus! Now I dry on thos purty white vinyl-covered shelves you get at Home Depot.