I used a thin piece of aluminium sheet metal and bent it roughly 90' and fastened it to the instrument cluster with silicone RTV. Drilled holes for the wires and fastened the gauges to the aluminium shelf.I really like the mounting you did for the TTO gauges! What did you use to secure them?
I have the TTO tach. Doesn't take up much room,is reasonably priced, easy to install and works well. The tach doubles as an hour meter.They also make a nice compact temp gauge.
I just noticed this thread is 4 years old. Hopefully the OP got his tach by now.