My LaCross has missed the charge cutoff at 200ma, but never at 500, so I'm going with that. As far as the chemistry is concerned, I'm still thinking that slower is better, but missing the cutoff is really not good, so 500 is probably a good compromise.

My old MAHA charger would miss cutoff on single cells when charging at the slow rate as well. This was a single-cell metered charger, -dV cutoff, but just one with "charging/charged" red/green lights.