To avoid a likely misunderstanding, I should clarify:  I understand that the rating per se doesn't drive the outcome of events and is just a capsule illustration of the underlying rating.  The only reason I included the rating in my description of the assumptions was to give an idea of the type of hitters I was describing.  For the purposes of my question, the actual mechanism for rating the batter's power is irrelevant--the initial question can be read without any reference to ratings without changing the question, which is:

When given a choice between a hitter with a lot of power vs. a hitter with only average power, and a choice between starting each of them in a high-homer park vs. a low-homer park, and everything else being roughly equivalent, which combination of hitters and parks will lead to the highest overall run total?  Should the high-power hitter start in the high-homer park and the average-power hitter start in the low-homer park?  Or does the reverse arrangement provide the higher net run total?   (Or perhaps it doesn't matter either way?)