oh man, if i would have had this months ago it would have saved me a lot of time. anyway, i am using similar settings and got Cura to work and love it other than the larger than actual print size. used your fix and now my prints are the exact size they should be which i have been trying to fix for months, thanks for sharing!
took some searching but the X3gwriter.py file is located at:
for me on windows 10. ended up having to search through the whole comp to find it. hope this helps someone else save some time.