I had assembled my bicycle in the 1990s with a Basso steel frame with Columbus SLX steel tubes plus Shimano components. Some Dura Ace. To save some money I made some compromises with the brakes. It also was mostly unused for three years. A few years a friend of mine improved it a bit and I used it then more intensively. Still there were compromises.
Since my best friend now co-owns a bicycle shop, I had access to an excellent bicycle mechanic: Jens. He is a real expert and is really good at modernizing vintage bicycles.
My main wishes were: better brakes, brakes and gear shifting together and more comfortable handlebars.
Unfortunately this caused an avalanche of changes. Jens had to get a lot of new parts and see how they could fit together.
Fortunately I now have everything Shimano Dura Ace 7800 components, incl. 2 times 10 gears.
Tried the bicycle today in rural north Germany and it was all perfect. The new brakes are a dream.
Just in time for the bicycle season. Many thanks, Jens!
Added: Just had a saturday tour through Vierlande, Hamburg's agriculture garden city. Driving on asphalt roads on dikes is just wonderful. Passing a rowing training center with rowers training for this years World Rowing Rowing Championships. Seeing storks flying low over me, huge white wild swans, sheeps with their lambs and then the river Elbe. Rolling with a racing bicycle. Truely magical.