NiMh do not necessarily follow lipos 1C 'guideline'. Its a safe rate, but may not be an optimum rate.

I have 4000mah and 4400mah NiMh pacs and charge them both at 5amps. What you want in a charge rate is to acheive a balance between punch and runtime if you're bashing. If you're racing, you want more punch from the packs. This would typically be done with higher charge rates than what a basher would use.

The 4500 and 5000 pacs I would try at 5amps (bashing), the 3400 I would try at 4amps. Make sure thay don't get too hot - if you can hold them, they ar enot too hot. They shouldn't get more than 120-125F when they peak.

If these are new, start with lower rates for the 1st 10 or so charges, then start pushing charge rate. NiMh will show some improvement over 1st several cycles some call it breakin.