Running a gauge thru a Bosch relay Options

[Literati914]

I’m adding three gauges (not doing a center console and not using it’s wiring) and want to confirm the connections for the Bosch relays I plan to use each, and figure out the grounds. Gauges will be Voltmeter, CHT, and Air/Fuel if it matters.

can someone confirm:
#30 gets “+” from the battery
#86 gets switched power from the fuse box
#87 gets “+” wire from the gauge
#87a goes un-used

#85 seems to call for a “-“ connection directly to the battery - but I’d rather not add a ground wire all the way back to the battery - I was wondering if the “-“ from the added gauge could go to #85, then loop it on to a body ground point?

Thanks.