I set up a folding bike with that identical gearing.... Schlumpf at the front, Torpedo Duomatic at the back.
I hated it. For most riding the roads are flattish, and I set it up to use the middle 2 gears for that, and of course the lowest for uphills and the highest for downhills. The problem was, I had to do 2 gear changes ALL the time - shift the Schlumpf, shift the Duomatic. And due to the brakes relying on kickback and pedal position not choosable, I couldn't install clipless pedals; even with normal pedals I had the uncomfortable feeling of wanting to fall over all the time.
So great concept, not so great in use.