However, as Leaf says, it's not worth the OSRS GP time to be in Herblore's Camp Habitat for the purpose of making potions. I do it each week just to earn an instant bonus XP bonus for finding all the jadinkos in 10/13 & any seeds found while doing that get planted & used.

They only last less than a minute therefore the best method I've come across for getting all patches with 1 dose of potion is to get at the Trollheim patch, consume one juju-based dose in a pot, REPEAT STEP, Ectophial teleport to Port Phasmatys & run to patch, REPEAT STEP, the cabbage port (explorer ring) to Falador patch, REPEAT STEP, Cloak teleport to Ardougne Farm Repetition Step, Camelot tab & run to Catherby patch, REPEAT STEP. It's not a lot of time to explore the scenery so leave refilling buckets, talking and so on until after you've collected Catherby.

The Repetition step it's obvious harvest(or clear if they died), super compost & transplant the herb and record the ones u harvested with the tool leprechaun. I prefer the Camelot Teletab and leave Catherby for last, so that I use less inventory space, and in the event of forgetting to replant , I'm able to go back the way I came to (most all of) the others by using an easy free teleport. Its also the closest patch to a bank and makes it easy to get inventory out or to grab any items you've lost

Also , for Trollheim it is worth having the rock climbing shoes on to protect yourself if planting 2 or more kinds of seeds, always choose the best or most expensive. Seriously, if he has membership and he powermine in the living rocks, along with the 16 lvls difference you have absolutely no chance , however if he's going to powermine iron to 99, he'll likely get the 99 dung at first.

16 levels isn't an excessive amount of exp in level 70. There is a need for 77 mining levels to obtain concentrated coal. You must bank it instead of powermine. Concentrated gold is at level 80. If he has an option to choose a dragon the odds are that it will be a close race in my opinion. It's not likely that the rates of exp will be different, however if you have a strong team, I think you'll make the cut first.

Yes its alot of xp because dung also isn't fast for lvls lower than 70. Furthermore, powermining is much faster, that's why i stated that he has no chance at all if mining at a level of power. 70 is less than 1 million exp, you need 13 million exp to achieve 99. The first 1m (even in the first 6m tbh) doesn't make one cent, and at 80 mining the buy RS gold miner has reached his optimum exp rate of less than 100k/hour.