Advantage of Parallel
Without going back to read Nigel Calder....
The life of a cell is maximized by operating as nearly as possible to a fully charged state. When one increases (doubles) the ampacity of the bank by means of paralleling, for a given draw on the bank, one draws down the ampacity/energy pool LESS (as a % of total) and so operates closer to fully charged. I seem to recall that Nigel Calder in the book referanced in my post above outlines the case with specific examples and generates expected life extension of the battery bank which is much much more than negligable.
I will go back and read it ASAP, but it will certainly be sorted out in this thread before then.