WriteBack in SSAS multidimensional or tabular? Embedding in SharePoint?

Hello,

I built up a Data Warehouse in SSIS. I run the OLAP in PowerPivot and also added some measures with DAX in PowerPivot.
The PowerPivot file is stored on a website built up with SharePoint and is visualised on this website with PowerView.

How do I set up a WriteBack?
There is no casual way to enable a WriteBack with PowerPivot. In an earlier project I already used the WriteBack functionality in SSAS multidimensional mode. Is there a simular possibility for WriteBAck in SSAS tabular mode? Shall I use multidimensional or tabular for the WriteBack? Is it possible to embedd and manage SSAS multi or tabular on the SharePoint website?

I plan to set up an additional Cube for the planning values in SSAS to enable WriteBack. (Yes I could have used just SSAS without PowerPivot. It is a PowerPivot project)


Best regards!
Jörg