You might consider style details from the models on top right and bottom right.
The pic illustrated an ASW post on waistcoats a few days ago.
My vest is made of a rather rough wool, not tweed. I have oped out for lapels, six buttons and the back that is made out of the same material as the front (leave shiny stuff for dress vests). Also, the length should cover the belt. In my opinion that looks cleaner, as the shirt does not poof out in the triangle formed by the bottom sides of the vest.
The general idea shown in RL pictures is right.