Completed preliminary component layout in MCAD (mechanical CAD) and ECAD (electrical CAD) today. The approach I usually take is to guess at component layout and board dimensions first in MCAD. Then import these dimensions as DXFs into ECAD. Component placement in ECAD becomes aligning roughly to the layout initially established in MCAD. It is very easy to make a change in MCAD and reupload to ECAD if needed. I have found that this approach plays to the strengths of each type of engineering CAD software.