I have a Lesser Tropical DB, with a vest, and for the winter Drapers 12oz in a herringbone, SB with a vest. For stripes I have a Smith 120s and Cashmere for the winter, and for Spring, Summer, Fall a vintage 10z narrow stripe. Both of those are 3 piece DB's. I have a bolt of navy flannel with a gray windowpane I am dying to use. For my furnishings, navy as a base color is the most useful.
I never heard anyone either from a mill or retail call it pick-by-pick. I am used to a totally different lingo than most people. For example "nail head" pisses me off. I was taught to never use that term. Most people think a birdseyes, pin dot, and tickweave are all "nail heads." They are not able to differentiate them. Today a customer referred to all three of those as nailheads.