Found some specifications on Sony PCM M-10
Mic Input (Stereo Mini Jack):
Input impedance: 22 kOhm
Rated input level: 2.5 mV
Minimum input level: 0.9 mV
Nakamichi CM-300 will have up to 15 mV on its output on a loud show (right up a rockband without PA-system). If the data of the M-10 is correct, it will overload the mic input. You can use the pad inside the CM-300 for loud shows. If you are some distance away from the stage it is probably not a problem.
Here are more information,
http://www.avisoft.com/recordertests.htm The noise floor is low (-122 dBu) for the M-10 but the overload level is too low at high gain settings. Dynamic range is limited to just 65 dB at maximum gain... Maybe a lower gain setting will help to increase the dynamic range by some some dB?
Roland R-09R seems to offer a better possible dynamic range. Nakamichi CM-300 and Olympus LS-11 seems to make a good combo.
Roger