Howdy, I'm new to this place, but I have been making leather gear for cops and cowboys for about 10 years and I concur with the postings i have read thus far. I usually dye the holster before assembling it and before molding.
I have recently started doing something a little different, with my wife's permission, of course. After wrapping and oiling the weapon, I usually use the plastic bag my newspaper comes in, and I have made a piece of leather that fits around the cylinder, which adds some space for those who wish to cock the weapon a little earlier as it comes out of the holster, I wet the leather with warm water, (but I have heard of using a mixture of water and denatured alcohol) and insert it into a bag from my wife's vacuum sealer. I then use the vacuum sealer, as directed, to suck all the air out of the bag and it molds the leather holster really nice and snugly around the weapon (and any built up pieces/areas). I have found that this adds to the safety in that the weapon specifically fits the holster (or vice versa, depending on how you look at it) and doesn't have any slop around room. You must be careful to position the weapon in the holster as you want to carry it and then it'll always be exactly there when you want to draw.
Now, the vacuum sealer bag will not allow the leather to dry, so you have to cut it open and remove the holster/weapon combo. I usually let it dry for a few hours to one day with the weapon still inside then remove the weapon and allow it to dry completely before i put any final finish on the holster.
This method will produce a holster that is really snug at first, but after use it'll soften up a little and be a bit easier. I like a holster that is fairly snug in the beginning rather than one that is too loose, because it'll only get looser as time goes by. This method seems to save me a lot of time rubbing/boning the contours of the holster around the weapon and if I'm careful i can reuse the vacuum sealer bag for a few holsters and then molding some smaller items before throwing it away.
If I can be of more help or you need something made that you can't find elsewhere let me know, my e-mail address is in my profile. Luke.