Hi @engilic. Neither the DrawingDocument object itself, nor the Sheet object actually have a 'Scale' property. Only the DrawingView object has the Scale, ScaleFromBase, and ScaleString properties. The Scale property has a Double type value, so it wants a normal number with a decimal point. The ScaleString property has a String type value, and is Read/Write, and it will accept the "1:2" type format and understands it as a ratio.
Here is a simple iLogic rule example that worked in a quick test:
Dim oDDoc As DrawingDocument = ThisDoc.Document
oSheet = oDDoc.ActiveSheet
oView = oSheet.DrawingViews.Item(1)
oView.ScaleString = "1:2"
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