I have done many Churches, big ones too, a royal PITA some were.
There seems to ALWAYS be something going on at a Church, either Church, Weddings, Funerals, AA + NA Meetings, Overcomers Meetings.
Heck, I heard Paranoids Anonymous met at one Church we were doing, but they wouldn't tell me WHERE they met.
Seriously, everything going on at a Church is MORE important then you.
Plus, there are people sometimes walking everywhere.
It really is too bad you weren't closer to Mel or David from Reef ?
This job is a big one, and not an easy one either.
Have you CONSIDERED possibly bringing in someone with good equipment and experience to help you ?
Lots of potential liability/safety issues here.
Just a thought