IMAX B6 is a fairly big charger capable of large currents. I don't know if it can reliably be configured for small currents, if it can and you are careful on getting the max current setting right, it will be suitable.
It's also capable of balance charging multiple cells in series which is a feature you don't need so end up paying premium for a more capable unit than your needs are.
Specs says it can deliver minimum 0.1A charge current, so it should work assuming you get a working non-counterfeit unit.
0.5A would be a good charging current for your cells, maybe occasionally 1.0A if you are in hurry but no more than that.
The problem is engineering reliable and easy-to-use contact pins for those cells.