Been giving the Zremesher Guides a go, but stumbled upon a slight problem. Trying to form a peak (symmetry on) but when the guides get close they start snapping. Still no idea what changing the brush size does but I can get closer to a peak.
I know this was 8 years ago, but I thought I would drop this here for anyone googling the question. You can control the snapping by going into the Stroke menu → Curve Modifiers → Curve Snap Distance. I think the default it’s set to 10 so I reduced it by half and got good results.