Not sure there is an "official" classification.
What I use for myself is an approximation of mechanical, transitional or Aero infulenced grip so (in gears)
1,2 Low speed corners (mainly mech grip)
3,4 Med Speed Corners (mix of Aero and Mech grip)*
5,6 High Speed Corners (mainly Aero infuenced grip)*
* A corner which is very interesting in this context is "pouhon" (turn 7?) left hander two turns after Rivage in Spa. At entry on high fuel its 4th gear and not much aero grip. As your speed (and aero grip) builds in 5th then 6th gear you can actually wind on more lock.
Ha Ha Andrew SNAP!