different approach, make the thumb hole a little wider to accomidate for the swelling, and use tape early on to compensate for the increased size. You can work on the swelling, but if for whatever reason your thumb doesn't respond, your out of luck. With a larger hole, as your thumb swells, you just take out a piece of tape and are good to go.
However, if your not use to using the tape, you might have a bit of an adjustment period trying to get the tape right early on, but later in the day, it should be a perfect fit without the tape.