Maybe others will tell you differently, but everyone I know who gets a cover for their CC with a T-top ends up getting the cover custom made. They cost more, but they fit better and last longer.
About 8 years ago I brought my Cape Horn 21 to Shirley's Canvas in Swansboro, NC and she made me a fantastic cover from Sunbrella. My memory is a little fuzzy, but I think I paid $1200 or $1400 for the boat cover, a cover for the console and a life jacket compartment under the T-top.
This past summer I bought a 2001 Parker 23SE with no bow rail, but a notch transom, so it's similar to yours but not exact. I lucked out and found a guy in my office who does boat canvas work as a hobby and he made me the cover below from Sunbrella material. Materials cost him about $700 and I gave him that, some extra and a few trips fishing. Both covers were built to last for years and I love the way the new one attaches under the T-top, it allows enough ventilation to keep the mildew away and does not allow rain to get in. Also all of the straps at the top and the bottom are in just the right place, which is difficult to find with an out of the box cover.
If you do decide to look into a custom cover you may want to post "Looking for canvas person in the XX area?". I'm sure there are people here who have recommendations and maybe you can get some prices to compare to the one you're looking at.
Here's my new cover over my new-to-me 23SE to give you an idea of what it could look like.
Good luck,
Gary
