For the Layman:
http://p2pool.hostv.pl/Pick one, point your miner at it, done.
Shares always have to payout to the current payout list to be valid on p2pool. The software does send it to bitcoind if it is a valid block to make sure it is broadcast as soon as possible. There is no way to change the way the payout is done. If you change that, you have to start the proof of work all over again.
As for high variance, pooling hashpower to a single p2pool address is possible. In fact, I ran such a pool for a couple of weeks. Instead of needing to find a block on its own, my pool paid out whenever p2pool found a block. I may revive it at some point, but there was almost no demand when I tried it.
The issue is when you search to see if they work the first results say they don't
Because people who don't know what they are talking about keep repeating it. Soon the hardfork will take place, and p2pool will be compatible with all ASICs. Now is the time to break this meme.
I also don't understand why so many people on this forum immediately attack each other - anyone that is not involved in Bitcoins is going to be reluctant to join or even post due to all the demeaning comments that are fired at you when you misunderstand something - which would will be the majority of new users.
You guys need to be more patient and just explain why something may be incorrect.
Maybe it is because people talk with confidence about things they don't full understand. This leaves the uneducated with false belief, which they continue to repeat. When you hear the same lie repeated 50 times because everybody takes hearsay as fact, it gets annoying.