Ive run into an issue in which linetype scaling is being very difficult.

What i have is 3 different CAD files.
1. Architects demo background set in metric units (mm)
2. A working drawing xrefing the architect background set in English units (inches)
3. A sheet file xrefing the working drawing in metric units (mm) with a 1:50 Scale viewport.

The problem im running into is that i cannot get the architects demo line work and the working drawings demo line work (and symbols) to both show as demo in the sheet file.
Ive set backgrounds and working drawings to a LTscale of 25.4 and 0.0393 to account for the metric conversion but i cannot seem to get it to work. Am i missing something? Any help would be greatly appreciated.