Sorry just realised I was still in general not in technical - my bad!

I have just picked up some gauges to go in the little space in the centre of the dash on my SIII LWB - currently just has a cheap and nasty no name brand tacho in the centre, got what I believe might be an original voltmeter plus a couple of other gauges (oil pressure and vacuum).

First question - should I ditch the cheap tacho and fit the oil pressure, vac and voltmeter as this is probably closer to what would have been on the vehicle originally? Or is it worth finding a spot for the tacho as well? I would like to try and keep the original look as much as possible. It has a 186 motor and many old holdens didn't have a tacho either.

Second question - assuming I fit 3 gauges where there is currently just one, is there an adjustment to stop the gear lever from hitting and possibly breaking the gauge when I put the car into reverse? Currently the lever just touches the dash when reverse is selected - obviously I could pull it off and bend it a little but is there a simpler way?

Third and fianl question for now - is there supposed to be an interlock or some sort of gate to stop reverse being selected accidentally? The lever goes across and needs some pressure to get it to the reverse position, but it doesn't seem like a lot of effort, I did it accidentally the other day. Are there springs that control this stop that may be sagging a little?