Nice touch, matching the legs to the trim.
If you phase the transformers you only need one common and a hot (3) for each line - pull a bus from end to end and tap into it for track feed where needed.
3M tap splice
You could also add one or two Accessory bus wires for say switch power and light voltages. 14awg also.
Use 12awg for the common as it would carry all of the current of the 3 lines and 14awg for the hot bus wires.
