One man's sacrilege is another's salvation. I like the Mafac Competitions and Ultegra derailleurs for it. Here's some ideas that I played out on mine. I started true-ish to original which was fine but not suited to the riding I wanted to do on it. In it's randonneuse phase it had a modern 2x10 drive train, Mafac Racers followed by Competitions, 700 x 36 tires, fenders and a front bag. It was my favorite setup for that bike. I got a chrome 1970 Professional frame and moved everything over, and the International became a lightweight interpretation of a Raleigh Sports for commuting and shopping. Now beicster has it and it's continuing to spark joy. As others have said, the International is a great canvas for many types of builds, and not so precious or rare that you should hesitate to make it into what suits you. Have fun and post pictures.