between all of these, the "42" looks nicest in #159 because the "ED" doesn't cover it too, much, with #220 being a close second place. the problem with 159 is that the ED looks too odd sticking out of the side of 42, and the problem with 220 is that the ED is too small to read except at large sizes.
i wonder how it would look to have #220, but wit the "ed" on the top surface of the 2, near the right edge?
or maybe to the side, as in #159, but much smaller, like a superscript?