The recommendation for 14 gauge minimum pertains to bus wiring. Assuming you plan to use a star wiring scheme with dedicated home runs, in my novice understanding of DCS wiring, I believe 16 gauge wiring should be fine given the size of your layout. Others with greater DCS knowledge can confirm or deny my supposition.
To able to use larger than 16 gauge with Faston connectors you'd need to either change to the 187 series (or larger) or alternatively step down the wire's size just before the 110 Faston connector. For what it's worth, I've found that even the 250 series (1/4 inch) without the shroud around the connector end will fit into the FasTrack tab and make a secure connection.
See page 8 of the following resource for compatible wire gauges and ampacity of Faston connectors:
