I would suggest a fork crown mounted cable stop/hanger like this one: https://www.amazon.com/Tektro-Front-.../dp/B006GHDRYC it will help avoid brake shudder: Technical Q&A with Lennard Zinn: How to stop cyclocross brake chatter | VeloNews.com

For the rear, here are two examples: https://www.rivbike.com/collections/...nt=23334913473

Mounting bolts can be cut down with a Dremel tool with a cutoff wheel, or an angle grinder, or just buy the right length at the hardware store. Don't tighten them excessively tight, you can mushroom out the end of the stud and cause binding.