Hi,
as suggested if you want to use extended star schema you have to use Cube, DSO is just like transparent table only/
Since you have 2 DSO try to build a cube and map the filed into it.
Similar type of char needs to be placed in single dimension (1:n relationship needs to be followed).
Once you create your cube and load the data, just use report (SE38) SAP_INFOCUBE_DESIGNS to check the health of you dim.
as you dim table should not be more than 10% of Fact table, you can check that using this report.
This ran for all the available cube in the system.
Thank-You.
Regards,
VB