Ian,
I have a couple of scythes for me and my wife (both OAPs).
Handles: me 6ft - size 3 snath, wife 5ft 6inches size 2 snath.
Blades: 2x70cm and 1x40cm grass blades, 1x65cm tough weed.
This lets us cut a 150sq metres of lawn and occasionally I go and clear rough weed areas in the vicinity as a social act.
It was noticable that our lawn has been green right through this hot summer when lawns alongside us were machine mowed (scalped) and burnt.
The main thing to learn is how to peen and sharpen the blades. This makes cutting with a scythe so easy.
You will feel the difference as soon as the blade loses it fine cutting edge, takes seconds to restore, then maybe quarter of an hour to peen two or three times a year in the cutting season.
Julian.