No matter which brand and model you start to home in on, Read their install manual - usually found on-line at their site - and pay attention to the "compass safe" distance for the install.
You will find that most of the Garmin stuff in the last several years must be 17 to 37 inches away from your steering compass.
We are currently looking into the newest Lowrance with the 4G radar, and that instument has a 7" safe distance.
Note that the sales droids at many typical retail stores like WM and none of the pretty web store sites will tell you this up front, and most will go silent when specifically asked.
As a wind-power sailor, you are shopping in a rather small niche market, with 95% of their sales and marketing directed at recreational day cruisers and fishermen, all with wide consoles on their power boats.
Your trip will require a good compass, with a current deviation card, because that's the only reliable "instrument" you will have if the power goes away.
Keep us posted on your choices and reasons. And, of course, Bon Voyage!