I have a one piece BikeGang cassette deal with 11, 14 and 17 teeth sprockets on my 2010 Brompton. I also have both a 38 and 58 tooth chainrings and use the 38 infrequently so stopping and shifting for a steeper slope and later upshifting back to the 58 is not a big wow for me. That gives me about 85 to 55 gear inches on the 58 and 56 to 36 on the38. I also a rear wheel with the SA177% 3 speed with similar lows but 103 gear inch high. No one I've seen has addressed putting an SA IGH on a P line but it may be fairly easy. They are heavy, though. Still, a 58 and 38 pair of chainrings are fairly cheap and require minimum installation effort.