Project Sizing Question

[galav...@gmail.com]

So I'm working on my project and I changed my background and grid spacing to millimeters but I can't seem to find way to change the side bar rulers to millimeters either. The only options I seem to be able to change between is inches and centimeters in the upper left hand corner.

Now the inches scaling wouldn't be so bad if the spacing between the lines were in 1/8ths or 1/16ths, but 1/10ths. Such an odd spacing, nothing my actual ruler or calipers go by.