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I was able to use the MFD functions without using the UP and DOWN Dial.
Basically I mapped the last four buttons in front of the G27 Steering wheel in gimx-config as below:
Logitech G27 Wheel Button 19 -> R3
Logitech G27 Wheel Button 20 -> L3
Logitech G27 Wheel Button 21 -> Plus (G29 Button)
Logitech G27 Wheel Button 22 -> Minus (G29 Button)
and the Gran Turismo Sport on the Logitech G29 Driving Force Panel set it up as follows:
R3 -> Select MFD +
L3 -> Select MFD -
Plus -> MFD Up
Minus -> MFD Down
I ignored the MFD Dial Up and Down functions and did not use them. I copied this configuration from the Dualshock 4 configuration panel.
Now I can select and adjust incrementally in the MFD Panel and I can play normally.