Depended on th track lenght. 45-7500 on a smaller track w/ around 90-120'
straits, and 6-8500+ on larger w/120-160' straits. This is the normal curve,
at times up to 9k+ when track is well prepped(smooth and damp) and it comes to you around the mid point in a race( Typical race from 25-30 laps ).
As far as handling pay more attention how a track changes under different
conditions. We always set up for the midway to later part of race, sometimes
including slight gear change, type of tire prep and air pressure, adjustment to crossweight ,over all rear width to fine tune stagger. and occasionally to add or reduce weight.
Butcher.