[FTC]: Custom Material and Wiring Questions

[electron]

Hello all!
While reading the TechnoGuard's Engineering Notebook (Thank you so much for opening that up, btw!), I noticed the use of what looks like stock aluminum C-Channel for angled bar. You can see what I mean here, and here.
Is that really some sort of stock channel/angle bar? Can I just grab some at the home depot down the road, and (most importantly), is it legal to use in FTC?

I noticed too that they used Kydex extensively, and I'm wondering if anyone has a good supplier that they would recommend.

And one more quick question I have is this:
I noticed that they extensively used custom sensors. Does anyone have a good guide for wiring the protoboard?

Thanks for you help, everyone!