3) Do you need it??
On my last engine (Merc) I had a water pressure, trim gauge, volts, fuel, and tach. Since it was analog and the previous owner disconnect the oil system and alarm I replaced the trim gauge with a temp gauge. This way I knew if I had an overheat issue.
If your trim gauge is a separate gauge I would consider replacing it with something useful.
What kind of cosmic bunny hole is THT? Breast implants seem to be a moral issue.... They're BOOBS!!!