737 rails dimensions

I already saw somewhere a site where was all dimensions of the "J" rails under the CPT and First officer seats. If vour have the adress of this site that would be very useful. I am working on the way to make my own "J" rails. After several months to break my head to know how I could make these complicated rails (too much expansive on the market)) I found the way to built it. If all works well the cost will be approximately $100. and functional... ie; rails in "J" shape with side displacement at the end of course (like the real ones). As always I will put all constructions details on my site. So, as I prefer to make everything with the real dimensions. So am I looking for these dimensions...Thank you,