Yep, what he said! Divide your boil roughly equally in runnings, so they are about the same. What I mean by that is don't put all your first runnings in one pot and the second runnings in the second, but put about 1/3 of the first runnings in the smaller pot and 2/3 in the first. Then do the same with the second runnings (and third, if you're doing two batch sparges). That way, the wort is roughly equal in OG and about the same % of each runnings. Then divide your hops the same way- 1/3 in one, 2/3 in the other.
A good guestimate is good enough.