I seem to remember that there was enough slop in the system to allow moderately high cable tension without nudging the derailleur inward or keeping the chain from settling down onto the small sprocket. The pre-indexing sprocket spacing was pretty wide, after all.

Funnily enough, many racers deliberately left the front derailleur cable loose enough so the chain would fall onto the small chainring when the lever was still 45 degrees away from hitting the stop. That way, they could easily shift both levers at the same time with their right hand.

Some company, Shimano or Suntour (can't remember which), actually designed that 45-degree angle into one generation of their downtube front shifters.

I wish I'd thought of leaving my Campy rear derailleur's cable slack enough to do the same. My thumbnail eventually wore through the paint on my Bianchi Specialissima and into the chrome underneath.