This (23 gram/0.9oz) mount clicks on the top of the Mavic Pro 1 & 2 without any further adhesives. Its shape allows battery changes without removing the mount.
More videos, pictures and instructions on how to mount things on www.djimounts.com
To mount a non-action camera you will need a 1/4" camera shoe like the one you can find here : https://www.amazon.com/dp/B018UJLIOE Here
you can see how different loads impact the battery life. Here
's a quick video on how to remove the drone from your footage.