Awesome Colorado rig you're building there and ochre to boot
I've been happy with the installs of vintage air on mine and my old man's truck. With his we are going to put in a booster electric fan in addition to the mechanical fan clutch to just keep the head pressure down as Andy mentioned. Both trucks originally weren't AC trucks but nothing a few cuts in the dash with the buzz saw can't take care of. We cut in the vents in my dash after paint and just had to take extra care.
Can't go wrong with an oe column. If you dont have a wild cam a vaccum brake booster should work fine and save a ton of build time.