Yes, I did RW spraying on the Canadian prairies. It was a lot of fun but hard to compete as the FW guys could do it a lot cheaper.
RW spraying is best for small acreages and places where fixed wing aircraft have difficulty getting in close, for example where there are lots of trees.
If I was going to do what you are thinking of doing, I would definitely go FW as there are more opportunities. Also, I understand you need a lot of hours these days to get a RW job.