Re: GPS and other displays, pedestal mount or other?
I prefer to have wind/speed/depth on the bulkhead where they can be seen from anywhere in the cockpit.
I have a chart-plotter mounted near the wheel with the auto pilot. I do most of my sailing by compass.
My boat has the compass well forward of the wheel; which is nice.. Easily viewed from anywhere in the cockpit.
I would say to have waterproof back ups (handheld GPS) and leave the ipad and other devices below. There are waterproof covers for i-pads; but they run about $350. Why bother, get a Garmin 78sc.
I do like to having the chart-plotter below and above. It is very nice.