We have always used max motoring N2 speed before activating the start lever to idle or rich on the classic. Motoring the engine cools the rear stages of the HP compressor and restores the correct temperature profile and therefore the surge margin. This is standard starting procedure with RR and P&W engines. GE on the CF-6 recommends a min N2 of 15% before fuel is turned on but we adopted the max motoring procedure on those engines as well.