I was all set to put the TR-1 on C-Dawg last winter, but went with the GHC 10, instead. I have a Merc 90 and a Merc 9.9 for a kicker. I had the Raymarine S1000 for the big motor and figured I'd put the TR-1 on my kicker. However, I was becoming unhappy with the performance of the S1000, so it wasn't too hard for someone to talk me into getting the GHC 10 instead. I have a tie-bar between motors for steerage. I also have a Trollmaster throttle control for my kicker, so I can control the kicker throttle from the helm seat.
With the GHC 10's heading sensor, I now have radar overlay on my Furuno chart plotter. Everything is mounted inside the cabin, and the pump is super quiet. It has the reverse feature, like the TR-1, and it has Shadow Drive so you can instantly take the helm when the AP is engaged at cruising speeds.
A few things that concerned me about the TR-1 is that it has to be mounted outside near the kicker, so for me that meant in the port lazzarette, which I currently use for storage of tackle boxes, wood shampoo (fish whacker), washdown hose, etc. The TR-1 also has more parts exposed to the elements to break. The controller is tethered to the unit with a cable (about 10', I think). The wireless remote is extra. I didn't like the thought of having a tethered controller laying around.
So, if I were looking at a boat with twins, I'd get the GHC 10. You'll have an AP to use on the way out to the fishing grounds, an AP to slow troll with, and an AP for the run back to the harbor. And with radar installed (which is imperative if you're fishing off-shore, IMHO.), you'll have overlay capabilities.
I'm not a Garmin rep, but I did stay at a Holiday Inn Express once, and this AP is one of the best additions I've added to C-Dawg.