Magnetic carriage Linear rail

I designed a new carriage for delta printer. It's mount on linear rail vs hole dimensions 23x24.

You can see optical endstop mount for that carriage http://www.thingiverse.com/thing:2151380

Magnetic carriage for Delta printer, 15x5 Magnets, 23x24 Linear rail mount. Gt2 belt lock. Endstop pin.