Both hives are heaving with bees - shedloads, to use the technical term - and very defensive. Clearing the supers with Porter or Canadian bee escapes will be a slow process, and even then there will probably be quite a few left behind.
Instead, can I leave the supers on the hives until the number of bee starts to decline? Then, clearing them could be a doddle. How long can I leave them? Until the end of August? Later?
How long is a piece of string?
[Actually, the answer is the cube root of a handful.]