There are two types of gas canister, threaded and unthreaded, and you need to get the right one. It's not a lightweight solution, the valve assembly and two canisters (what i carry) weighs more than a pump but it's quick, small and easy.
Falling down on the basics just ruins the whole project, first and formost the bike is a piece of machinery designed for a purpose. Is it meant to be riden or hung on a wall as art? If it's art then it's more pleasing to look at if works and everything looks "right". When you show it to people...
I'm probably teaching you guys to suck eggs here but my understanding is that gear and brake outers are made differently, gear outers have linear wires and brake outers have spiral wires to resist compression.
Brake inners and outers are bigger and stronger because there is a greater safety...
I don't have any "Fast Bikes".
Of course they may have been fast before they came into my possession.
Point taken though, comfy and slow it is, i'm torn between an old Peugeot and a single speed with more comfy tyres, both would fit the bill nicely.