gauge wiring, need help

[ttles714]

Twin 2001 sx250(ox66). Starboard ignition switch activates starboard tach, Fuel Management, and speedo...Port switch activates port tach only. I want to reverse. How do I get the port Switch to power up the FMM and speedo ? Is there a "main Lead Wire " that powers these gauges ? Does it come from the switch or are they powered off the activated tach ?

[boats.net]

There is a guage wire harness connected to each switch and connects to gauges, would have to move wiring connections on speed and FMM to other gauge harness