I just picked up the PVC this morning, and ordered up the Loc-Line from Amazon, which will be here Friday (thanks Amazon Prime!). But I'm still left wondering about what screws to use to attach the collars to the spindle mount. I went back to the PDF file available via GrabCAD. It shows they are tapped M4, but it doesn't mention the pitch of the threads. Big Orange has a few different ones available (M4-.7, M4-.5, M4-.4, M4-32). From what I can tell, M4-.7 is my educated guess, but I'm hoping someone can confirm that for me.