Neovibe LFO timing

[mdame]

I recently built a neovibe and am still tweaking it.  I am pretty happy with the sound after a few mods, but I dont seem to be getting the same swing or heartbeat rhythm to the LFO that I feel I should be getting.  I am getting more of a sine wave out of it.  Does anyone have any tips? 

I did build this in a crybaby shell, and reversed the wiring on the speed pot to be fastest toe-down, using a log taper dual 100k.

[mdame]

Perhaps I haven't found the balance between the Brightness and Darkness (R47) trimmers?