I'd put the oil pressure where the tacho is and move the tacho on to the steering column or somewhere up a bit higher. That "glance" to look at the rev counter down where it is might turn in to a look to see what the revs are will mean less time looking at the road. Thats my theory as to why i'd have it up higher.
A good tip i learnt is with the other gauges, say the temp gauge, turn the gauge around so the needle points straight up when its at operating temp. It'll take a glance to know if somethings wrong cause the needle will be off centre.