If you go to www.boatstogo.com, you can see their ideas for biminis in the accessories section. SA won't let post links for some reason, but it is easy to find.
That said, the bimini is small because the boat is small. My wife needs to avoid the sun as well, so I have considered this thing. Another approach is to get the new tech fabric long sleeved gear that is cool in the summer and nice wide hat. I worry the bimini would be a danger in a thunderstorm. YMMV.