have any advice or references for someone stretching canvas for the first time?
Get some good canvas stretching pliers. You can spend $150 elsewhere if you like, but they're not much better than these.
https://www.amazon.com/MyLifeUNIT-Professional-Canvas-Pliers-Stretching/dp/B01DXXOA3I/ref=sr_1_3?ie=UTF8&qid=1510017628&sr=8-3&keywords=canvas+stretching+pliersAlso an air or electric staple gun. You'll use lots of staples. Stretching is easy. Corners take practice. YouTube is your friend.
I make my own stretchers from 1X2 wood strips. A chop saw makes the mitre joints easy. Drywall screws attach the pieces without glue. Once the canvas is stretched the whole assembly becomes aircraft wing strong.
Coatings are mostly PVA glue. I've had good results using regular Home Depot PVA glue diluted 2:1 and applied with a foam roller. Way cheaper and easier than a spray application.
For controlled conditions and for your own use (rather than for sale) coatings are voluntary IMHO. I have several uncoated large canvas prints on my walls in (sometimes) direct sunlight that have been there for ten years. Zero fading or colour changes that I can see. Epson K3 inks on Lexjet Sunset Matte canvas. Coating prevents damage, but other than the cats, there are few print hazards in my home.
Walk before you run. Start simple, adapt as necessary.