Is there any problem with using Inkscape except to get scaling correct?
BTW i found this
https://wiki.inkscape.org/wiki/index.php/Units_In_Inkscape
EDIT:
I see version 1.0 is in rc, looking good https://wiki.inkscape.org/wiki/index.php/Release_notes/1.0 /EDIT
I am a newbie to SVG and Inkscape, just investigating yet…