Getting ready to re-do instrument panel

[chesapeake724]

Ahoy, gents

Well, mechanic says he'd be much happier if I brought the boat over in Jan or Feb, so with the fairly mild fall I'm going to try to sneak in a re-do of the instrument panel, including install of new switch panel. I'm half way into The 12-volt Bible for Boats so I will have a good feel for best practices. But thought I'd run a couple questions past the board ahead of time.

Tach and fuel are the only gauges that are associated to the ignition (turning ignition key energizes/gives power to those gauges). My question is, does this have to be this way or can the both gauges always be 'reading', even with the engine off? That would simplify the wiring, because the gauges are then independent of the engine controls.

Everything else on the boat is just an on-off device (nav. lights, horn, bilge*, etc.). *Bilge pump would additionally be direct-wired from the float switch to the battery or bus bar(s) of course.

Next question, is for those that have already made a panel out of 'Starboard', what thickness did you use? King also makes a 'Starlight' sheeting that only comes in black and isn't as rigid. Anyone know if it's sturdy enough?

THX