In this case,I took a small plastic container (yogurt cup)placed it inside the guitar body. Then ,over the course of about a week,kept filling the cup with warm(steamy) water,covering the sound hole to keep the moisture inside the guitar body.

I did this about 4 or 5 times a day over the course of a week,while tightening the dowel on the Bridge Doctor at very small increments of about a quarter turn or so.
Keep in mind,I didn't use boiling water for this process,as I didn't want to introduce enough heat to loosen any glue joints.

Had this been a plywood top guitar,I probably wouldn't have been so concerned about cracking the top.
As it was,I'm not so sure how much of my success with this project was just dumb luck that it didn't crack!

DB.