If you are running bar-end shifters then full size V's and Tektro V levers is a good way to go.
There is a hidden nightmare in all this with Shimano's change in road lever cable pull in recent years to NSSLR, this may be why you don't get much from the Dia-Compes. Have you tried the Tektro...
My father in law worked exactly like that in a bike factory somewhere in West London in the mid 1950s.
My first almost decent bike was a Halfords Olympic, bought secondhand on the Caledonian Road in 1984. It was gas pipe of course.
...although nobody had ever won the TdF in a Shimano-equipped bike until Armstrong.
Also a lot of Shimano's innovations are more marketing than real innovation. Hollow BBs were a case in point: a strong story at the expense of undersized bearings with a pitiful life. Similarly a lot of the hubs...