After completing 12 Amarr sites, I now have enough standing to do the Standard (level 3) one which allows mining barges to enter. So I fitted a cap stable Procurer for as much tank as I could (double MSB for 69hp/sec, 67% EM, 64% Therm) and took it out.
I have tried 3 Standard sites. Failed two and then soloed the third, mostly due to pure dumb luck with the random NPC Orca placement (they are the ore drop off points). My Procurer’s tank wasn’t stable with whole room aggro, but it can last for minutes before having to warp out. This is not a problem however, because the NPC’s only aggro on warp in and when I use drones against them. If I ignore them they will eventually switch over to the friendly NPC’s and leave me alone.
This site didn’t feel dangerous at all, the NPC’s were just too easy to avoid. It’s was also possible to solo this as long as the NPC Orca’s spawn close to eachother and close to the asteroids.
I haven’t tried it, but I speculate that a 10MN AB Procurer that warps out and back in (to clear aggro) will be able to solo a fair number of these sites as things currently are.