So, you think the uneven balance word not average out over a test like this and would favor one pool all the time?
Well it would be spot checking every pool in the list, so it'd favor no pool really - and it would almost certainly not be properly balanced between the pools.
Chad is going to dedicate 1 rig per pool, thus avoiding this issue.
That is probably the closest you'll get to a fair measurement of pools - assuming the rigs are identical, stable and run from the same location.