I do not even do void opal mining any more after doing 2x painite hotspot mining. I would estimate that 75-80% of every rock you hit with a prospector has painite in a 2x hotspot area. Some have upwards of 60% painite content. I get bored with mining, so I use a Python with 160 tons storage and I can fill it up in in about 25-40 minutes, just depends on how many pirates I have to deal with. It is not uncommon to mine 2-3 rocks with barely moving your ship, if they all have 40% plus painite and are within range of your mining laser. I average about $60-70M credit/hr. Not off the charts, but good enough for me.
EDIT- Also, as a way of judging, I use 5 collector limpets and my prospector can have 2 active limpets. First time I went out I took 120 limpets with me and was discarding them constantly. Eventually, I set out with 50 limpets one time as a test and was able to still fill my hold and eject 3 of them, so 47 limpets used to fill my hold of 160 tons. However, since limpets are cheap, I usually go out with 60 and that is more than enough.