A decrease in the compass budget = an increase in the electronics budget. When you headed south Scotty? Please leave the cold fronts and cold weather in NC.
Bob, The structure scan and high def transducers only have to be within one foot of another for the downscan overly feature to work properly. All that is is a display view that overlays the downscan ontop of the standard sonar. If the ducers are more than a foot apart the two images my not align properly. To be honest not many people including me use the overlay feature.
I have another idea to throw at you with your setup. Have a dedicated FF on one side and a combo chartplotter on the other. I agree with Fernando, I like Furuno.Here is a deal going on THT for the new FCV627 FF unit which I really like. Then on the other side get a Garmin chartplotter as big as you can afford.
My turn for plotter Garmin all the way and for FF I have been looking at this one http://www.furunousa.com/products/produ ... sh+Finders can be had for much less