Mike...yup, Roger did this for larger quakes and I looked at his results. This was discussed on this page a couple of years ago. There was a whole range of angular distances and they were called FFAs here (I guess for Far field aftershocks?). We did not look at smaller quakes...say. M3s. I forget, but Roger may have graphed M8s and following quakes over M5. There was a suggestions of a peak near 102 deg and may be 108 deg (I may not be remembering correctly) but there were peaks all over the place and so these may not have been real/may not have been significant. I probably have Roger's results on my old computer or a backup or something, but should not spend the time to dive into this here at this time...working on a manuscript.
And, better to get out of the house and enjoy the couple inches of snow and sleet we got last night...being daytime, not likely I'll ski into barbed wire like I did last winter.
Chris