Ordered the 11-28. Installed it yesterday. Was pretty easy to swap, took awhile to adjust the derailleur. For users considering this change you just need the park tool to remove the old freewheel. Then its thread off, replace, thread back on.

Paired with the 56t crank I find everything perfect for my cadence. 6th keeps me around 18mph and 7th puts me into the 21mph range. 6th for me is now my primary and 7th is no wind flats or downhill. Fastest I got was 27mph, a tad scary on the folder.

The freewheel is louder than the stock unit, not sure if some break in time will change that.

G4's arrive tomorrow and that should be the last upgrade...already thinking Brompton in a year or two for air travel.