Yep, Splinter, that, exactly, is my regret (not having done the 45 uppers that would have been the starting points for everything else).

In the end, I would have tweaked the 45 thing in all likelihood, to minimize the depth issue (making the 45 section 1/2 the depth of the other cabinets deeper).  That is, where there is no solution there cannot be a problem, right?