It's good to meet you, Jay, and it's great that you are checking out options before you actually have chickens.
If you have the ability to build your own coop, that's generally the best route. Most pre-fabs greatly overestimate the number of birds they will properly house and many are flimsy. However, not every pre-fab is horrible just as not every chicken keeper is a carpenter. If I'd had to build my own coops, I'm sure all of my chickens would be dead by now.
I've seen photos of well-built "hoop coops," and your plan looks good to me!
Welcome to BYC, and feel free to ask anything, anytime. There's a wealth of knowledge in this community and folks who are always willing to help.