This article about windows partition alignment explains that checking the alignment offset of dynamic disks can be done with the DMDIAG tool to get the "relative sectors" property.
With dynamic disks the StartingOffset property, reported by the win32_DiskParition wmi class, can be deceiving (as explained in the article).
Is there a wmi class that provides this "relative sectors" info or is there a way to calculate it manually with the info wmi does provide?