John
I'm not a Leather Worker, nor have I stayed at a Holiday Inn Express (that I admit to)
in my sordid past. I have also never used "stuff" on the inside of my holsters. I do "fit" my holsters to the guns however. The true leather guys will probably want to lynch me, but here goes.
I first wet the inside of the holster with Hot Tap Water, then before it can cool, I stuff in the subject gun, with a 16th inch thick leather pad on one side, all in a plastic bag. Before placing the gun inna baggie, I give it a light squirt of WD-40 just incase the baggie should "leak." I let it set to dry to shape for couple three days. I prefer to let the holster dry simply at room temperature. The resulting "fit" of the holster allows the gun to come out lickity split.
Just My Take