cryptoalts only 88% effective
Same here. 12-13% DOA is not acceptable.
Use different nodes! US East is a bit overloaded with hash right now (looks like one big farm on it), so get that spread to lower DOA. US West and US Central could take a fair amount of load off US East. Same with EU1, EU2, and SG1 - try to keep them balanced. Use the link below to see individual node stats. 
I was once supporting somewhere between 1-2 GH/s for BlackCoin when BCPool was down getting DDoS for entire week, and things were fine. But hash rates were pretty well spread.
It is especially important for smaller miners to use lower hash rate nodes. Other than that, because my pool is P2Pool based (the only multipool out there P2Pool based I believe, and thus hopefully DDoS resistant), so once the hash rates get high (over 150 MH/s on scrypt per node or 500 MH/s X11 per node) the difficulty on each node starts getting very high. This leads to high DOA rates unless you're the one contributing all of the hash!
http://cryptoalts.com/poolinfo/ to see individual node hash rates.
I wasn't expecting this much hash so I guess I should been very clear right from the start about keeping the hash spread - sorry! Anyway, worst case, you at least know where to set your failover mining addresses if you cannot obtain a low DOA rate.

Don't forget if you are interested to give hybrid mining a shot!
http://cryptoalts.com/hybrid/