Feel free to contact me about the Furuno 1815. I installed mine 2 years ago and I am still learning. Gonna have to compare notes.
I got the holes drilled in the mounting plate, I was supposed to get my new canvas top for my custom radar arch today, well that didn't arrive so I'm on hold till it does, in the meantime I'm rearranging my Chart plotter/fish finder to a new spot, easy peasy, have to see what tomorrow brings.
I would be happy to exchange notes, as I know only what i have read in the operators instruction manual, so your light years ahead of me.