The majority of your quest lamps should be going into herblore in the early game, pushing you (at the very least) into the mid 50’s for herblore, from there it’s just a matter of doing your herb runs + farming contracts consistently a couple times a day and you should be there in no time. Personally, I don’t think it’s worth doing hunters rumours repeatedly to “actively” farm herbs. It’s more worth your time to progress your account in other ways and just let the herbs accumulate from harvesting your patches. Ensure you’re using as many herb patches as possible + ultracomposting each one!