In my experience the auto Re-size can be problematic in visual results as well as performance, if you design a dashboard for one screen size, and someone opens it with a slightly different screen size (but same device type) it may shift or squish the view in a way you do not desire or intend. I have not used auto sizing with the different device layouts.
As far as a navigation work around, there are several ways to build menus and navigation into dashboards (links below) but you might also try placing all of your dashboards into a Story, this will then be 1 "tab" on server but allow you to click through the different dashboards.
Note about the Story option (taken from the VizPainter link above):
Use a Story. Another nice option in many cases. However, you are dealing with snapshots of dashboards and vizzes, so be aware that things like global filters and parameters won’t carry through from one story point to the next. Still, consider this option and apply it where it makes sense.
Hope this helps!
The story idea is a good one! I'll see how that works out with the different dashboard sizes.
I was going to suggest URL actions, but since you are not the one publishing it to server, you will not know the URLs ahead of time