I put them in my boat last year. I screwed the top directly to underside of the gunnel. And the bottom in to the casting deck. I can take a few pictures if you would like?
I am very happy with the cargo nets. Easy/cheap to install too.
Based on my research, the EchoMAPs can share way points but can’t share live quick-draw maps. I may need to just keep saving my maps to an SD card and copying the information over to the other unit/SD card. Similar to what Trent was saying?
I think I will proceed with buying the 93SV, transducer, and Garmin’s data sharing cable.