I don't even know if audio recorders will accept a wireless mic. I suspect your best bet to find out would be to talk to a person at a real electronics place (as opposed to Target, Walmart or Best Buy). Even Radio Shacks around here have folks who are electronics buffs first and sales people second.
I gather you are male from posts elsewhere, so it won't work to suggest you flip the microphone over your bra, but you may want to put a safety pin inside your shirt in an area where the collar will cover both the pin and the bulge of a small microphone. Wear a shirt with the shirt tail out cover the top of your pants pocket and that will cover the passage of the wire to your pants pocket where the recorder is.
As for settings, when my microphone is plugged in it overrides the other microphone settings for the unit. I tend to leave volume a little on the high side to catch everything but not at the highest setting where it gets some distortion. Then when I playback on my computer I can adjust the volume to a comfortable listening level.