I use to double clutch in the holinger (non synchro/dogbox) when in street duties, altho, once competent with the gearset it was very possible to 'time' the shifts and allow for the rev speed to match the gear speed on up and down shift, further enhancement of the technique required no clutch at all cept for stationary approach and departure.
Normal synchro box, rev match and heel toe all the time, very efficient form of driving, less stress on the box and driveline, but isnt so flash for fuel economy
