Howdy sir.. and a good looking pair of pistols you'll be sporting, no doubt!
As for leather, the good thing about Opentops is they will work with any Colt type holster. Most of my stuff is San Pedro Saddlery, but Big Ed has been in poor health and I've not seen him online much.. I'll have to check on him. His work is excellent, but not always the quickest to get.
Rudy at Black Hills is a good guy and a Texan to boot..
Grouchy Old Bear who used to post on TFS seems to have excellent work and his slimjims were very nice.
Wild Rose Trading Post has unbelievable work and Chuck knows his history, so you can get it really right.
There is also a local guy, Drew Causey with Lone Star Leather.. he shoots with the Driftwood bunch and he does nice period work as well.
Too many to really pick from, but if you want black, then I'd go with Big Ed or Rudy.. both of their blacks are true and hold.. my pimpin' black rig is for my OTs.. sweeeeeet!
Adios,