Once you pop a roid, it respawns after DT at a very tiny size. I believe they grow after each DT. Not entirely sure. Usually takes 5 days or something similar for them to reach full or near full size. It might be different for 0,0 ore like crokite.
Btw, you can get low sec ore (Hedbergite, Hemophite, jaspet) in high sec via exploration. Found a big dead space site in 0.5 with about 4 hours of low sec ore.
Ore location via faction
Excellent detailed system ore map of #belts, true sec etc
Personally, i think Caldari space is the best place for ore mining once you start getting multiple hulks and increased yield. More time with the lasers on the better. Having lasers on for 3mins (or 2.5) to only end up with 30 kernite and then only having 10 small roids isnt good in the long run. No GS jihads up here that ive seen.
Regarding macro miners, steal the ore. Stolen loads in the past. Can have some fun too, fit a MWD to a cruiser or bigger and you can ram them far away lol. Sometimes you can eject your own can and remove theirs and they will put ore into your can and flag them red so you can blow them up. Not all macro programs work like that but a few do. Lotta fun
