If it's a true burl, you might get uneven drying by leaving the bark on in spots and not coating those spots. On a regular block that's has end grain on the ends, I just seal the ends a quarter to half inch with wax. I keep it ready to go in a covered pie tin and just soften the wax with a plumbers torch. Then, I just quickly dip the ends. Plan on loosing wood, and don't be disappointed when you do.
Good luck, Craig