Just a "short" answer. Been travelling again...

I had to think into why you all read the proposed gauge is somehow ment to be big. Then i realised the giant 600px screenshots (for testing purpous in qmlscene on my 4k screen) and me not giving a mock-up of the whole screen placement might have lead you into that, sorry.

The gauge is kept simple and readability optimizes for the exact reason so it can be displayed rather tiny! I was thinking about the same height as the other lower items (menu+compass). That would not be wider than the current "n km/h" then also, but much more readable imho.

This post will be followed up by some clarifying screenshots as soon as i am back on my workstation.
Also i realize the background circle do not fit the overall ui, Thatmight get an update.

Thank you for taking my proposal serious anyway
I did not know gauges where already discussed.