If you can't do it with one anchor, don't
Les has more experience than I, but here in my 2 cents. Some anchorages are well protected with sand/mud bottom and if condtions are calm and with maybe a sentinal weight added to the rode makes you feel sufficiently confident to raft 3 on one anchor overnight then go for it. You can't do the bow and stern anchor setup as you probably know since you will end up with 30 feet of slack at low time and the boats can swing and wrap the anchor lines around themselves or around the rudders, props etc.The state mooring buoys (I think) are rated for #2 27-30 feet or less boats to raft. Have fun, the crowds will be gone.One last tidbit, check the tide table, sometimes you get only a 3-4 foot tide during the 8 hours you are sleeping, if so I would think about bow and stern anchors.