As I said, redirect isn't the solution to the problem but I thought I'd implement it anyway, after all when I do fix the problem its effectively a low cost option anyway.
What this does is shifts via a redirect (using 302 rather than 301 as I might decide on something else in future and let people render what ever they want) to the nearest "valid" box. Valid here is considered to be a box of size (width and height) of a power of 2 and based around a grid with a box starting at 0,0. So effectively we find the nearest power of 2 to the width then just move down from the current point to find the nearest one. Not exactly rocket science and its effectively doubling the number of hits.