I am not at home so I don't have the receipts--but my best recollection was that the "Factory" canvas was about $2500 for the 25. I got that because they could supply it in about a week. My local canvas worker who did the Tom Cat-for about $4100 was busy, and it was going to be a month. If I had to do it over, I would have gone with my local canvas guy, who is very good. The seams were all finished, a Tenera Gortex thread was used so that the seams will last much longer. The fit and finish was far better. The frame was 1" SS tubing,4 bows and self supporting, with a panel which would zipper out between the first bow and the cabin awning rail VS 3/4" aluminum, with 3 bows, and not self supporting. If custom made you will get a better product and what you want.
Having said this, the "factory" for the 22, I currently have, is better made than the one I had made for the 25. I suspect that different technicians made the different camper backs, or the person who ordered the 22 had specified better components.
Look at photos and backs in person. Things I want on the 25, is full SS tubing support fore and aft. This way you can use the forward support as a railing, and full zipper out of the first panel, either part way, or fully, which makes it easier to get in and out--the zipper should be able to be used from the outside, and zipp from outside of the boat to the center.
In the back, I feel that probably taking the full camper back to the transom. This gives more room in the cockpit. I like as much clear in the back--the amount of windows on the side are optional--I happen to like less, so you have more privacy from dock walkers. I also like the fine mesh insect screen, with zip out clear vinyl, and a way to secure the clear panels on the top up under the bimni. I also like to use high quality clear vinyl. Clean vinyls are available from 20 to 40 Mil.--and Strataglass or EZ 2 CY which are higher quality vinyl are preferred--but more expensive. A good enclosure will last 10 or more years even if up full time. If you take the enclosure down, it will last longer.