OKAY, since you have considered all your alternatives and you have determined what size modelisme echelle h0 you are planning to construct, your next action is to figure out how you are going to support everything. Here is the key to getting to grips with your model train design.
I should have known that would happen. After all, because of my daddy's hobby when I was a child, I still have a liking for model railroads. Then there was my current hobby, building and accumulating dollhouses.