Remixed Kossel Carriage Truck for 2020 V-slot

I remixed this for compatibility with optical (photo-interrupter) end-stops by adding a pin which enters the photo-interrupter slot.. I plan to use this along with the end-stop mount found here: http://www.thingiverse.com/thing:450238

I moved the fastening holes vertically a couple of mm to make sure they are clear from the pre-load bolt passing through the carriage and also deepened the 20x20 hole pattern so that they pass through, which they didn't seem to previously.

This is my VERY FI