I have an Azden wireless - Lapel mic. Azden WLX-PRO Lavaliere System
It uses 9v batteries and works very well. I do not hard mount it to my video camera, which I suspect can be a problem.

I did a seminar a while back with video and it came out exceptionally well.
Questions from the audience were handled by the speaker who repeated the question and then answered it.
IMO, this is really the best way to handle questions from the audience, because as the speaker repeats the question it is clear what was asked.

Yes, I realize you see people speaking into handheld mics on television. I'm not sure how to handle that. I may try to use a double input 3.5 to single 3.5 input to the mic transmitter unit. This paragraph might be a good topic for discussion. I have a couple of cheapo mics with 3.5 plugs for use with the computer. I think for a good audio response I need a better mic.
Then again, I have audio-technica ATR2100 with USB and XLR outputs. This might work using some type of adapter.
I would have two mics interface with the transmitter, which would be a efficient way to do this.

Azden does make a handheld mic version using the same transmitter and receiver. I'll look into this.

Yes, I am very satisfied with the Azden wireless lapel mic setup.