This post is a little late in joining the party...but I'll toss it in there anyway just in case you're still wondering about how you're going to do the wireless thing.
Our singer brought a very old Shure wireless system along with her. In all honesty, I don't even know the model - but I'm guessing it's a predecessor to the current PG series (the receiver isn't rack mountable, there's no frequency selection capability, etc. .... and knowing that our vocalist is always broke.... it HAD to be the "value" line).
We've been used it every gig we've done over the past three years. I slap the receiver on the side of the house rack using Velco - and toss it in the "Miscellaneous" case when we're done. We've NEVER had a lick of trouble with it. The one time I thought it was having problems - I put a new 9V battery in the mic and all was well again.
It and a PSM200 wireless In-Ear system is the only wireless stuff on stage - so we're not using it in a "busy" wireless environment. Neither do we wander far afield from the transmitter (the far side of the dance floor - so...40-50 ft max?). The mic has an SM58 "...ish" appearance - and compared to the "wired" SM58's the rest of us use - it's the hottest MIC on the stage (the channel input level gets set at roughly 2/3rds the level of her "wired" SM58)
At first, I was a little leary about the thing - but after 3 years of using it - I'd buy another one just like it in a second. It hasn't given us a lick of trouble - in any venue.
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The SpaceNorman