What they said

... the rice knives seem to use cheaper metal and are inexpensive (<$10), whereas the kama use harder steel and run $15-25. Its a brittle steel and so it doesn't peen like a scythe blade. I like both, but favor the kama because it is always green around here, and I can cover more ground with a kama.
I agree with the scythe being faster. When your vegetation design shifts from cutting swaths to selective cutting you might increase the labor per meter, but you also allow the
canopy to close, so I think there is a role for both depending on where you and where you are trying to go in evolving a system.
I spent one season working on a farm managed by one of our big companies (Eclectic Institute). They would grow their own, assemble wildcrafting crews, and buy in material to fill their inventory. But you are selling at half the price you'd get if you were selling direct to a retailer. I would start at the
local retail end and work backwards. Every town in Washington has a little herb shop. Look for naturopathic doctors and ask them any local sourcing. Otherwise you're shipping -- either way you are starting a business, because if you cannot consistently provide an interesting portfolio of high quality products you will likely not sustain a clientele.