In addition, I highly recommend adding the following two lines to your
bitcoin.conf:
blockmaxsize=1000000
blockmaxweight=4000000
This enables your P2Pool node to mine full blocks. I'm not sure if btc1 changed its defaults, but on Bitcoin Core the default
blockmaxsize and
blockmaxweight values are 750 kB and 3 MB respectively, meaning that if you left your bitcoind to its defaults, your P2Pool node would be mining artificially smaller blocks.
Now that SegWit has been activated, using blockmaxsize=1000000 will prevent your node from ever creating blocks with more than 1 MB of data (including witnesses). The best way to ensure that your node makes the largest possible blocks is to have this in your bitcoin.conf:
blockmaxweight=4000000
WITHOUT any value for blockmaxsize. Bitcoind will not use the default value for blockmaxsize if a value for blockmaxweight is manually set.
https://github.com/bitcoin/bitcoin/blob/master/src/miner.cpp#L83P2pool itself also has a 1 MB limit right now. I will need to check whether p2pool itself limits the block stripped size to 1 MB or the block serialized size to 1 MB.