How do you measure and mount a seat?

[low&slow]

I have a pair of race seats that came out of my dads old boss's baja truck. Anyways, I bought a set of seat mounts out of the jegs mag and they fit my seats real nice. Question is, I'm trying to now mount the seat to the floor of the truck.

How do I know it's centered for the drivers side?

And how high should the seat sit?

Is question number 2 depend on what you're actually comfortable with?

The mounts are adjustable up and down as well, but I'd rather have a starting point rather than a guessing point.

Any help is much appreciated.