0.1C is a "forming charge".
The best rate is 0.5C - 1.0C on a charger that uses delta-v on a normal basis. You have the tool to prove that to yourself over the long run. More simply, Delta-V is the detection of a slight DROP in voltage when a nimh battery is charged. The battery actually drops a very tiny amount of voltage when it is full, signaling the end of charge. Quality chargers such as LaCross and Maha/Powerex detect this very well - UNLESS the current being used to charge the battery is not strong enough to force this small drop of voltage to raise the flag. Hence, 0.1C is too small a current to force a DV, and you lovingly cook your cells away - slow roasting them even if they don't feel warm! That is one reason that forming charges on the LaCrosse and Maha are merely timed.
About the best thing anyone can do is visit the Candlepower forums - those guys are into batteries about as much as all of us on RR are into radios. This is a good starter thread:
Appropriate Charge Rate for NiMH Batteries
All the members of the Candlepower forums are extremely knowledgeable, and I would advise paying attention to the threads from "SilverFox" in particular - although many many more are just as helpful.
On that forum, you will also find specific battery recommendations, such as why old-stock of Energizers rated from 2400 mah and up are bad ideas, and why the RECENT 2300 mah seem to be ok for energizers - that is for a standard nimh cell. Other manufacturer's battery history and makes can be checked as well with reports and data from the users.
You don't have to believe these guys - if you take the time with your smart charger over the years, you'll see that what they say is true. To save time, keep your eyes open for SilverFox (just one of many great contributors)
It is a balancing act. Do you really care about getting the longest runs and lifecycles from your batteries, or is it ok to only use half their capability if you got them very cheaply? Should you run "Low Self Discharge, LSD", or regular nimh batteries that self-discharge 10% in the first 24 hours and 1% every day thereafter? If you are a photographer, or someone who burns through a set of cells every day, then regular nimh's with their slightly larger capacity are for you. If you go awhile without using the scanner, then low-self-discharge may be in your best interest.
All of this can be found on CandlePower whose members are smart-charger fanatics with data, photographs, charts etc to actually prove things.