Not having to double clutch.

I've done it. Several times. One place I worked had a 7600 International with an HT570/Eaton 10 speed (unsynchronized). It was the only way I could get that POS to shift somewhat smooth.

 

You need to be sent for drug testing I bet. //half teasing.

The proper method with a manual big truck is double clutching to syncronize the transmission properly with two particular engine RPM's necessary to do it correctly coming up or going down on the tree.

I don't care about the one clutch, floating or standing on your head. Ive done all of that at one time or another. Maybe we should bring back the Mack Two sticks to really make life interesting for everyone. Weed out those who cannot drive in a short order.