1) This is the first and foremost rule of hareming: respect other people's property. No overlaps on boys unless it's agreed upon by *both* harem mistresses, and if you feel like "borrowing," make sure it's sanctioned. I think everyone can deal with that.
2)Number of boys: we're sticking to seven for now. Keeps it easier on writing-purposes and keeps more boys open for anyone who feels like joining.
3)Try to respect continuity, k? If we decide to put the hall in the mountains for a weekend, don't write about laying out on the beach. It just helps to keep confusion down.
4)Comments are encouraged! We all like hearing about how good (or crappy) our writing is.
5)Lastly, lemons are fine, but put a filter or an lj-cut on them to warn off readers who don't feel like hearing about your dirty, dirty thoughts.