OP, as much as I'd love to have that extra hash rate on p2pool, if I had that kind of setup, I would almost certainly spend the time to setup my own pool and mine to it as eleuthria (who certainly knows a thing or two about running pools) mentioned. Of course, that also runs the risk of poor connections to the network and orphaned blocks, so considerably higher risk (losing the full block vs losing a few shares on p2pool).
Maybe see if -ck would be willing to work on something with you. He might know a thing or two about mining and pools...
EDIT: I actually just saw -ck's reply above to use
www.kano.is.
So let me get back to the basics of your original question. PPS does not suffer the effects of variance. You get paid for every share you submit. The value of each share is calculated as the block reward divided by the network difficulty. The big PPS pools (f2pool, AntPool) charge you a fee for PPS mining, 4% and 2.5% respectively. Now, f2pool does give you alt coins (NMC, HUC, etc) to help offset the fee, so at the end of the day you probably end up making about 98% of expected earnings after everything is factored in.
PPLNS pools (like p2pool,
www.kano.is, antpool) are very affected by luck and the luck swings can lead you to making considerably more or considerably less coin than expectations. I actually have a very long running thread (which I need to update with the last month's data... will hopefully get to that tonight or tomorrow) showing actual earnings of an S3 on p2pool since about Christmas of last year. You can clearly see from the graphs that there are ups and downs, but overall I have made more BTC than expected payouts for that hash rate. If you go through the thread you can see there were weeks where p2pool found no or very few blocks and others where p2pool found more blocks than expected. You can also see the effects of luck. There was one week where even though p2pool had better luck than expected, I actually made less than expected because of how many shares I had on the chain when the blocks were found. Anyway, if you want to take a look, that thread is here:
https://bitcointalksearch.org/topic/nastypop-vs-standard-p2pool-891298.
On a more personal note, I don't support the behavior of either f2pool or AntPool. They both perform SPV mining, have caused forks in the chain previously, and run shoddy software that produces empty blocks.