If no one replys, you can do what I did on my Mac26S. Measure the width between the port and stbd points on the coaming where you want to attach the structure and measure the max height to clear the boom. See what is out there that's close. The sides will spread a little wider or narrower if you don't find an exact match. I still ended up cutting mine down a bit to clear the boom.
Another thing I learned the hard way. Use machine screws with washers and nuts to attach to the boat, not the wood screws that come with it. A high wind ripped mine out and scratched the gelcoat a bit. The bimini was closed.