Add a $300.00 hardchrome job to your pistol and you have a $2500.00 pistol built the way they want. Add $500.00 and get a full custom one that is near perfect for $3000.00 from several great smith's on this forum. It is a little more but only cry once.
With a bull barrel & no slide lightning it will be heavier than a 5" with it all at the muzzle, bad, put in a bushing barrel & lighten slide & will weigh the same as a 5".
You need more than .004 as the hood and breachface will take a pounding and the gap will shrink fast between the comp & slide. I use about .011-.012 and it settles in at about .004