I would use your battery box for every recording first of all if you don't have a preamp. I would go mic in and leave the recording level set on 3. The preamp on the M10 is top notch. If you get a preamp go line in and recording level on the M10 on 4 with the pre @ 75% gain. These are just suggested starting points that seem to work well. As far as the other settings on the M10: I go with Record (manual), low cut filter (off), mic sensitivity (low), REC mode (96kHz/24bit), Memory (Memory Card), Limiter (off), Cross Memory Recording (on), Plug In Power (off), PRE REC (on), Battery Setting (nimh), Backlight (always on), LED (on). Record mode is just personal preference as is having the Limiter off, also backlight always on. If you don't use rechargeable nimh batteries you will need to set battery to alkaline. If you find yourself in a situation without your battery box make sure you use plug in power. After you start recording lock the device. Slap some black tape over the manual/auto rec switch. I think I covered everything.