I know a number of people have problems with overly course trim with the 727.  This may be old news for some, but I just discovered that if you have a registered copy of FSUIPC you can edit the sensitivity of your trim button.   The values suggested in the manual give about the same degree of control as the cruise trim control button in the CS aircraft (which of course can only be operated with the mouse).

Editing trim effectiveness in the aircraft.cfg file is not really a good solution as you will use the range of trim needed to takeoff.