Half to full back on a road course, depending on conditions.
If you have the time, change your mounting location for easy access.
edit - I posted quickly and did not give much info.
My 260 is a well prepared, mostly gutted track use car without coil overs and the L series engine still kick`n.
It`s set up for track events and handles well for not being a "race car".
I have the non-vented Toyota calipers up frt and drums in the rear.
I use Carbotech (panther plus compound) pads and shoes and run Hoosier racing radials.
And I do ajust the shoes after each outing (after a little cooling down)(the tire and brake compounds I run alone would make "my setting" differ from someone elses setting)
John (as usual) said it best, test, try this / try that.
I have been on track at Summit Point and VIR only (both several times).
I find my settings to be pretty consistant at both tracks (with simular conditions, wheather, heat, etc.)
Now as far as the placement of the pro valve, I wanted to be able to adjust the brake bias on the fly (if it rains I`m not coming in to make ajustments)(and by the way some of the best learned skills were on a wet track)
I`m only offering my opinions, not what the "hot set up" is.