BlooAnemone

Did a lot of prospecting in E&B live but actually remembering where things were: apparently not. However, I do remember a website, resurrected courtesy of waybackmachine.org: The Claimjumper. The breakdown by sector includes density, asteroid types, and mob type for roamers. The breakdown by mineral type indicates what things could be prospected from what type. Not exactly ideal, since the site tends to be slow, but a lot of information. I hope it's helpful.

The lower playerbase does seem to lend itself to this theory. I remember often mining in groups, even if I didn't start out with the intention to do so, upon arrival at the asteroid field there would be people there and grouping would be an easy option. But, it does seem that it is much harder to thin out the random mobs floating around before re-spawning. Also possibly related, the density of the mobs seems to be an issue in some locations (not necessarily just in mining locations). I don't know if that's directly respawn related, but it there are patches where the mobs just seem to be packed a bit thicker than they were in live.