I agree with jgwinks. There are local "canvasers" in most every major port.
These are all custom projects.
My observation is that there is a LOT of variability in technique, method, and design from vendor to vendor.
I expect there is also a LOT of variability in the cost you might pay for YOUR project. I will not get into specifics here now. But contact me if you'd like to explore more specifics. OK, one example, "Will the zippers be sewn in so the cloth "covers" the zippers protecting them from UV light, rain, wind and other outside environmental influences?"
If it was me, I would visit a MINIMUM of a half dozen boats like yours in your marina / neighborhood who have had this type of project done in the past 3-5 years by a variety of vendors. Get their input on what they like and don't like about the design and execution of their enclosures.
That will inform you on BUDGET, FEATURES, and ultimate ENJOYMENT of this key piece of gear on your boat.
If you are a seasonal weekend boater vs. a year round fulltime live aboard, the budget might be different. We have become fulltime liveaboards. This part of our vessel is a key part of our HOME. We will not skimp when it comes time to replace this part of OUR boat/home.
The TOP panel is the one that ages faster than the sides. SO, talk with your vendor about chafe. Should we double up on the material where the Sunbrella material comes in contact with the S/S tubing? Should a more abrasive-resistant / UV durable material be used on the TOP? Those are questions I would ask. ((No canvasser wants to replace the TOP only if it leaks or is worn in a few years after the job.)) How long will you own this boat? "Do you want this to last 5 years or 12 years?"
Some vendors take a LONG time to get the project done... (not what they promised). That is a major frustration of dock mates we've talked to. Manage that factor too... on top of everything else I've mentioned.
Lastly, the COLOR of the canvas is important. Consider YOUR personal cleanliness regimen. If you are the type that spends 30-60 minutes cleaning your boat every time you've come back to the slip VS Go a week or three between cleanings, know that your canvas and isinglass requires cleaning to stop mildew etc. A light color (tan/yellow) will require more diligent wiping down with Spraynine on a sponge or other cleaning agents. Darker colors are a bit more forgiving. Admittedly, we are not all the same... and it matters.
I wish there was a "shaded" darker isinglass product for the top 1/3 of all the isinglass!!! But, that's a different subject altogether.