@mr_j @woland can't thank you enough for all your painstaking help with this and amending my set-up so I can create the visuals for the show Saturday!
It was a real please working with you and I feel very grateful for all the trouble you took - and giving me a step by step guide.
I am still puzzled why, for example, Orbbec don't have any custom software to operate their depth camera from a mac.
I will let you know how it all goes on Saturday and hope we can get by communicating between the two macs through their internet network.
All best wishes, David