I obeserved today a phenomenon
Suddenly my stales rate went drasticaly up allso the whole machine was lagging badly, im not sure about what did cause that, i could not find any activities in my logs so that wasnt caused by any apache related activity, just p2pool and the chains was running. I suspect that this has something to do with peers; this could be intentionaly or cause of a bug. i realized that stales and orphaned shares on the p2pool operating chain are probably caused trough this.
The solution is simple: restart the pool more often, a node that is running to long probably causes a higher amout of stales or even orphans...