Hi Russell,
Thanks for the response. Unfortunately, what I'm trying to achieve here is actually a workaround from using the Create Building Scene Layer tool. This is because (see my other forum post here) one of my Revit families "Generic Model" is too complex to keep in the SLPK and is freezing my PC when i try to run the tool. Therefore, I was looking at other options.
To be honest, this is proving to be a bigger problem than I realised, as my other post today indicates that I can't even host a simple multipatch FC to AGOL using Pro 2.5. So i have a few bugs to squash before I can get a decent workflow.