Many of us believe that consistent alignment of the tabs and slots of the sabot with the lands and grooves of the barrel aids accuracy. It may or may not be true. But consistency in any step of the loading process can't hurt - right?
Anyway, here's what I do.
Use a flashlight and a "Sharpie" marker to mark the location of the lands on the muzzle.
Then place a bullet in the sabot and partially insert it into the muzzle, bullet first. Leave a small section of the slot exposed and rotate the sabot until the slots are centered on the grooves and the tabs are on the lands. This assures maximum and consistent contact of the lands to the sabot.
Use a small three-corner file to file an index notch on the outside rim or the muzzle at the slot location nearest the ramrod.
Every time you load, place the sabot's slot at the index mark. It will make you feel good.