To Be Honest, if you want to alch overnight, the best place would still be Pest Control because of the number of legit and bot's there. Try W301 it would be the best bet. Again, because there are a lot of people there and other bots + legits there too = less chance of getting banned.
Try it, you shouldn't be banned. I recently got 70 magic on my new pure doing this overnight.
Goodluck with whatever decision you take

.