Go and rent the unit from Dan himself, pretty darn cheap too.
Try the newer E unit, tiny and light and Lightpipe i/o too.
We used 3 unit ganged together for a national spelling Bee with 24 open lavs on 12 kids, the hosts, and the judges. In the unscripted "scramble" round we had no way of knowing which kids would get the word first, these saved the day at FOH , the IEM feed and in the truck for the 2 mix program feed. We later edited the whole thing but for a clean feed on the day it was great. Also, if the talent is fidgeting, that will trigger the lav and become very apparent very quickly.
If they are seated you should have no issue.
Brian in Halifax
Brian Power (I)