I also found that if I ran a BFGMiner proxy to connect to my pool of choice, then pointed my Minera with 10x Gridseeds on it at the Proxy, i would get much lower HW errors. Probably because I left the Diff at 1.
But what would I run the proxy on? Another computer? Another Raspberry Pi? (I do have B+ on order. Should be delivered Monday.)
Would it be worth running another computer just get a lower error rate? What does a Raspberry Pi B+ burn?... 1.5watts? 2watts?
I guess it might be worth it.