Hi Mr. Wizard,
The best protocol for preventing permanent sulphation of the plates is immediate charging, preferably to 100%.
The old suggested method of desulphation was slow gentle charging -- which is exactly what a solar system does. I think the numbers form 7:00 am to 8:30 am show that is exactly what is happening with my system. 0.6 amps into 875 amp-hours of battery bank is not very much. Plus most solar charge controllers already do a PWM charging style.
I'm not trying to discount the pulse desulphator in any way, I'm just pointing out that you are doing a lot of things "right".