My thoughts on buffing are given in this article:
The amount of pressure you can apply depends on the type of finish you are buffing. For lacquer, I hardly apply any pressure for fear of melting the finish. Just place the surface of the workpiece in contact with the wheel. For polyurethane, you can apply more because it's not as prone to melting and streaking.
However . . . applying more pressure does not necessarily make the process more effective.
Here are directions for making a mandrel that allows you to mount a buffing wheel or bowl buff on your lathe: