@125mph, trim is the middle position of the front shifter that is meant to be used on a dual chainring. It is not a full shift, just a slight movement of the FD that allows you to crosschain without rubbing the chain on the FD. It's standard on modern road levers but I've never seen it on TT shifters. I have no experience with the r2c shifters so if someone else says they offer trim, I'd take their word.
I've been using the 2012 Red FD and crank with the lower end 500 TT shifters. There is not a trim position on the front shifter, though the FD does yaw as you throw the shifter through its range. No issues.
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