I have a single Trane 5Ton XL14i Compressor (410a) matched with a Variable Speed Air Handler (4TEE3F), Trane EAC, and WR 1F80-261 Thermostat on 1 zone (servicing 2 floors - 2700sq ft in New York). When we were shopping systems, all bids came back with either 5 Ton split systems or 5 Ton single. We run the air handler in continuous mode since my wife and daughter have bad allergies.
We asked for Comfort-R to be turned on when the system was installed. The system is ramping up / down as
described and is quiet, but I find the humidity level a bit high for my tastes (approx 60+%). It can go as high as 68% overnight when the indoor temp stabilizes and the outside temp is mild (the compressor may not not kick in at all).
The Thermostat normally is set to 71-72 degrees.
I find that the level drops to (50% or below) when the system runs longer when it changing temps (i.e. 76 - 72).
A normal maintain cycle rarely exceeds the 1 + 7.5 minute run time. The serviceman will be in next week for my annual visit.

Several Questions
1) I believe the fan is set at the standard 400CFM per ton, I was going to have it reduced to 350CFM.
Would this help?

2) I have seen some correspondence with regards to Jumpers on the control board. That a jumper should be installed between Y and O for Comfort-R to work properly. The DIP switches must be set properly as my system is ramping up / down. What does this jumper do? If the jumper is not installed and the Comfort-R DIP switch settings are turned on, what would the result be?

In the installers guide that I have, one of the diagrams show a Single Stage Cooling / 2 Stage Heat system
(I only have Single Stage Cooling) - with the following note
'Connections to "R", "BK", "O" and "Y" must be made as shown for proper operation of Blower
with Humidistat in cooling' - I do not have a humidistat.
There is no diagram for Single Stage Cooling alone.

3) Would installing an external humidistat help as well?

Thanks in advance.