Leonard, Man do I feel for you, if that is of any value. It looks like the guys on here have a wealth of info, so that is on your side.
I have been planning to make the same conversion, [6 lug vs your 5 lug] and have already purchased the power booster, under floor bracket and caliper brakets, so I will be waiting to see you finish before I start! I had planned to buy the calipers and rotors and hardware at NAPA to save on shipping. I had also planned to vaccum bleed with a tool I bought but wonder based on the comments of others if I should go with the speed bleeders?
You have mentioned a couple times the combination valve and wanting to remove it, what impact will that have on the overall performance of the system? I had not planned to install one and go only with a rear adjustable valve, but then read on one of the brake manufacture sites that this is not street legal. Can anyone comment on this? My thought behind no combination valve was that how would you know which one to buy for a truck that using disc/ drum that has a different mass and distribution than todays cars? With the exception of the pita of the safety vavle it seems cleaner and easier to use the combination vavle.