All sounds correct. Also be sure that you pushed the thumb button all the way down before attaching the cable, so the very first click of the finger lever causes the cage to move to the right.

Be sure that you have attached the FD cable properly. It is possible to route the cable such that is shortens the effective lever arm length and that will make it harder to move the the finger lever.

My other thought is that your shifters are quite old and may need an overhaul. Be sure that your cables and housing are all in good condtion.