Not quite what you asked for, but we use ours kept fully open inside the chart table. Dosn't get too hot (thought it might) and protects it case of unexpected splash down companionway. On the list of jobs is a "frame" of wood beading on the floor of the chart table to stop it moving around. All the many wires are hidden away inside the chart table too. Can alway prop chart table lid open at times of heavy use.
I've considered changing chart table lid for perspex so could see laptop through it, but the Admiral would have a fit if I suggested loosing that much wood from the interior.
I have been very happy with the RAM-mount system on my boat - I fitted it a couple of years ago above my chart table and have had no problems at all with it since, including a transatlantic.