First battle jacket advice?

Hi! I'm about to start looking for stuff to make my first battle jacket and i have some questions.

1. I am planning to go monochrome with the band patches (red on black with red contrast stitches) so can i hand make all of them? Or do i have to scour for ones to buy?

2. Why do some people cut the collars off? Is that just a preference, or is it some unwritten rule?

3. If i want to add studs or spikes or other metal, where is the best placement in your experience so i don't accidentally stab myself or someone else?

I love metal and i hate capitalism, so i'm trying to DIY as much of the process as i can. Thanks in advance!