In another topic we got sidetracked when I mentioned something I do quite frequently. I work in churches quite a bit - video and audio recording, and live events and getting microphones (and occasionally a camera) in the right place is tricky. I've put up a couple of pictures of the type of building that causes grief.
The right place for the microphones is often terrible for video, but attaching things to these buildings is very difficult due to the age (1400's onwards in this area) and the understandable concerns of the church authorities.
We use them to suspend stuff from chain winches and the roof steelwork, but they're very flexible and soft and these strops/slings can be used wrapped around the stonework so a catenary wire - I use 3mm normally - can then run left to right across the space, carrying the stereo pair and their cables without any signs of damage when removed. Here we tend to use ripples
https://www.google.com/url?sa=i&url=...AAAAAdAAAAABAN or old fashioned steel wire rope clamps ( 'dogs') to secure the cable, but that's a bit tricky - so what I do is secure the wire rope properly at one side with these devices and then drop the other end down through the sling's shackle so it gets to ground level. This way you can measure, then attach the mic cluster, then pull it up and hang some sandbags or weights on the end to get the mics up. The strops/slings can be choked and they are surprisingly gentle on the brickwork, even under tension. You still need a ladder to attach them of course, but those extendable ones work pretty well. Putting these up is fairly stress free compared to any other way I've tried. You still get occasional concerns, but once they touch them, they normally understand they're non-damaging. I've never taken a picture of them in use, but I'll try to next time out - hopefully before Christmas.