Roger, the work you did correlating FFAs and the largest X-class solar storms also had few earthquakes in day zero. So, there is probably something wrong with how day zero is calculated. If you can get the day zero-day1 looking reasonable, and there is a bit of a maximum there, then it would be good to run this proceedure where the initial quakes are only M6+, followed by M5+. The input file again should have aftershocks removed...otherwise, if there is a M7.5 with 20 aftershocks > M5 within one day, you might run all 21 quakes to see what follows, and get some peaks because there might be, for example, another M7 with 10 aftershocks 20 days out-which would give you 400 time lags of 20 days....where there should be only 1.
Chris