I'd say make everyone a farmer and gather a lot of food THEN make everyone a researcher and Research Like Mad. With your stored up food they won't need to do anything else for a while.
Actually, I rarely have more than a couple dedicated farmers; one is enough to feed many, many villagers, and when food gets low any skilled farmer will farm more aggressively.
This makes room for more researchers from the get go; one farmer is enough, and I usually have another cross-trained, usually as a healer, in case that farmer dies. Healers don't do much if not healing, so it's an ideal dual-function skill.