filing a new jazz bass nut

In the midst of defretting my jazz bass, I chipped the stock nut. I bought a new Fender J bass replacement bone nut to take its place- thing is that it isn't filed!
It's exactly 2 inches in length so I'll need to shorten it to 1.5 inches. Then I need to file grooves for the strings but can't find specification for string width anywhere on Fender's website. I suppose I'll try to mimic the width of my partially chipped nut- that is unless anyone has the specifications for it?

Anyone have experience filing down bone nuts?