It appears as though this might be available from factory now - I received my first S1 yesterday and during brief testing appeared to load balance between 2 pools without me updating anything.

Once I receive the powersupply I am going to run the S1 with (750w dell with breakout board from gekkoscience), I will test further (I didnt try percentage hashing as I didnt quite realise what was going on) and report back here.