I had 7 speed Exage Biopace on a Bianchi several years ago but don't remember the exact configuration. It was my first index shift bike, but only on the rear as I recall. This may not apply to you, but a recently acquired Peugeot with Simplex shifters had a front downtube shifter that always kept slipping. I kept tightening the black plastic thumb screw, afraid I would break it. I finally removed the thumb screw, and put a thin split lock washer between the screw and the lever. Worked like a charm, it hasn't slipped since. I'm not a fan of down tube shifters, but this Peugeot was mostly original, so I tried to keep it as is.
When I bought the bike it was missing the front cable, and the broken Simplex front derailleur. Funnily, I replaced the broken FD with a Shimamo Exage, which worked perfectly, with the Simplex set-up.
Exage front, Simplex rear, Stronglight crank, kind of Franken-French, but it works.