hellboy, as i recall, when i used to do it i didn't have to turn up all that much, and i don't think you will either..why don't you just try it at normal level and gradually turn it up? can't go wrong doing it like that.
btw. the Countryman earset mic looks to me like it is sort of a cheek-mic type of arrangement..the mic doesn't look in the fotos like it's in front of the mouth. wonder if i have an infringement lawsuit there????LOL

I was setting up with my akg mic today in the garage,
using the shortarm plug-in boom, and i was trying to see what everyone is talking about re disadvantages of working that way...and i can't locate the problem. First of all, I don't find the mic blocks my vison of the keyboard to any significant degree. Secondly, one doesn't have to face
straight ahead to sing or speak into the mic, one can just
turn their head if not 180, then at least 120, which is all
you need. you stay on mic by moving your body to the side as you are working the mic.

i'm still in the market for a headset mic because I just won a Korg X50 demo on ebay, and I'm going to set that up with a strap to use as a keytar, so I'll want a headset when
I use it that way. ( i TOLD you i was a lunatic!)

Miami Mo