I'm ranging ghouls atm to see if I can get them to give up a champion challenge and I get about 31k exp an hour off them. Is that on the low end of exp per hour, not counting chinning?

Yeah it's pretty low. Are you using a bow and arrows? or knives? And its best not chasing a challenge scroll but to get them through normal training.

Using msb atm which is, yeah, nooby, so no need to rub it in. :P Since it's the same drop rate of champ scrolls whether I camp or not, it's a mute point.

It's not really a moot point, though, because you are paying a lot in opportunity cost by camping a rather poor-dropping monster and not getting much XP.

 

Not sure why people still use the MSB when there seem to be much better options.

Try out slayer. I got my first champion scroll by training slayer and raising combat through slayer. There is now the focus sight and hexcrest you can add to a slayer helmet to be able to get the black mask boost to all sides of the combat triangle. You will get plenty of tasks that give the chance at a champion scroll so why lose the opportunity of slayer experience, money, and ranged experience by camping at a poor exp/hr monster.

Most people don't encounter gouls in their normal training, since they are a terrible monster to train on; but yeah, that's pretty low exp/hr.