I know this is an old topic, but thought I'd offer an alternative in case anyone was looking for a sun shade...
Anyway, I needed a bimini also, but on small boats, they can be a real pain to install, use and live with, not to mention expense. On small boats, they tend to be short, and LOW, as the boom and mainsheet are limiting factors. I have a factory installed bimini on my CP Legacy, but found that it's so low that it's really difficult to sail with and still see and move around it. It seriously hampers getting on the foredeck. When sailing heeled over, I lose about 50% of visibility, and have to scrunch down even more than I do just to fit under the thing. I dislike using it at all unless at anchor, and then it's still too low for comfort.
After agonizing over details and cost of a real bimini for my Precision 21, I decided that maybe all I needed was a sunshade to use at anchor or in a slip. I bought a Taylor Made Anchorshade III, that is pretty much a big, square umbrella with an adjustable height center pole that ties off to shrouds, stays or whatever else is available on your boat. It's much cheaper than a bimini also.
At anchor, you can swing the boom out of the cockpit, and raise the umbrella to a much higher position than a bimini will ever go. And it stows easily in it's own bag. I've slowly motored with it in place (<3 Kts), and it was fine. It's not made for high winds. It makes hanging out on the boat at anchor or slip much nicer and cooler.
Of course, the downside is you can not sail with it, but I compromised when sailing by wearing a wide brim hat, with lots of sunscreen, and a long sleeve polyester Columbia fishing shirt with UPF 50 (not as hot as it sounds, just don't get the nylon one).
Here's a link to the manufacturers website if anyone's interested. I bought mine from iboats.comhttp://www.taylormadeproducts.com/anchorshade/