Current Amazonian, my opinions are my own.

I love the emphasis on writing these papers to drive a meeting, and 6 pages is an upper limit. I personally prefer trying to condense it to 1 page. I will sometimes need get Product, Tech, and Ops to agree on something, and I find writing the paper really helps me solidify my argument. If you're just trying to get your team and principal engineer to agree to a design, however, the 1 page technical doc you mentioned is sufficient. Full 6-pagers are more common when working across orgs, in my experience.