OR2BAJA,
Cerakote is more durable on the metal than Duracoat. Something to consider.
Your updates and upgrades sound pretty reasonable to me. I don't agree with the Bubba comments. It sounds like you are doing your research and pretty much know what you want. A Higgins M-51 is an excellent candidate for this sort of project. It is not like you are messing up a museum piece. Just making a good working gun better.
I would think twice about shortening the barrel very much, other than cleaning up the crown, unless that Hogue stock is too butt-light for you. Balance lost is not easily regained.
Welcome to the Campfire. You sound like our kind of guy.
