So after the above 3 posts and some quick reading, let me see if I am getting this right - I would drop back to a single chainring on the crank, use the SA hub, it has 3 spds & is controlled by the/a left handlebar shifter, and a rear derailleur/right handlebar shifter for the freewheel (currently 6 spd)? Producing an 18 spd, probably with some gearing overlap. I can get up to a 48t outer if needed...