Welcome back. I can relate to tinkering. I tend to do that myself.
My question is this. Is this going to be parts driven or is there a specific use intended? I believe that is going to drive the tinkerage.
My thoughts, assuming the bike is going to be an all-rounder go anywhere bike.
- Go Simplex. If the RD you are going to use has the pivot closer to the upper jockey wheel than the center, you will be able to handle a wide range of cogs. Even the standard model does well. The SLJ front will also handle a wide range. Both from personal experience.
- Agree with iab on the silver rims. Pelissier 2000 hubs or Maillard 700.
- Stronglight 49 or TA crank. 46/30 or even lower on the small ring.
- I can tell you I am running 38mm tires on a similar frame. Rear wheel all the way back. The pic you share looks like you already know that.
Oh dear....I think I just built one of my own bikes.