Jerry,
I have encountered the same thing with my circuit breakers and auto reversers. Use a few inches of the largest gauge wire that will fit in the AR1's connector, then step it up to 14g (either a solder connection or via a terminal strip).
If you send me a PM with your email address I'll send you a photo showing how I dealt with that.
I have two reverse loops, each of shich is about 13' long and contain five loop tracks plus three stub tracks. My loops are twenty feet or more away from my command station. Both auto reversers are mounted on a board near the command station with a pair of 14g wires on the output side leading to a control panel mounted at the edge of each loop.
Each of the panels has a terminal strip splitting the power eight ways--one for each of the five loop tracks and the three stub tracks. I wanted to be able to cut power to each of the tracks other than the outer one (main line) so seven go through SPST switches. 14g wire pairs from the panels run under the tracks, forming what is in essence a power bus for each of the tracks. Feeders were dropped through the roadbed/subroadbed and soldered to the rails and the respective power bus.
Thank heavens I was able to find surplus wire to keep the cost down.
I started to wire a large reverse loop on my way out today and ran into a problem. The loop is large and I had feeders going into it realize that was wrong cut the feeders. My problem is that the reverse section is about 15 feet long with a siding. What's the easiest way to get feeder wires to that section without them being way too long?