Okay, I square rooted the count in every box of the array, this gives a buttery-smooth finish on the 4 months of data.
The decompressed raw log is over 500MB and contains over 32 MILLION points. Decompressing the logs (i.e. converting deltas to coordinates) alone takes several minutes.
Again, 3000x3000 image attached.
Edit: I have also attached 4mo_smooth_nosingles.zip which is the same image but where data for cells with single counts has been discarded, this makes it a bit clearer still.