I need recommendations for front derailleurs that have flat-walled cages, not the sculpted cages like most modern FDs have. The derailleur will be used with a TA crankset which has very tight clearance between the crank arm and the outer chainring. Rubbing of the outer cage against the inside of the crank arm was common with these cranks, and the only way to avoid that is with a really flat cage.

So, what FDs have been used successfully with TA pro / Stronglight 49 cranks? Looking for 70-80s vintage if possible.

Oh, and the FD should have at least 24T capacity as well and work with a triple, as I will be configuring the crankset as either a triple or wide-range double.