For me, "effective range" is something like the range over which I can hold dead on and be within two or three inches either way. So, with 100 yard zero, that would put the "effective range" at about 130 yards (about 3" low). And that is probably getting at the margins of the envelope in terms of energy, also. On the plus side, a 100 yard zero appears to be a little over 1" high at 60-70 yards.
And looking at the results from a ballistics calculator, if I zero at 75 yards, I'd be down 4-5 inches at 130 yards.
So I think I like the suggestion to zero for 100 yards best, and figure on not taking any shots out much further than 125 yards or so. Realistically, I would expect most shots to be under 100 yards.