Do NOT buy 100w flexible panels and mount them on a hard bimini. They don't produce rated power, they get much hotter than a normal panel due to no air flow underneath, thus no cooling
and loss of power due to heat. Some of them have been recalled due to a fire hazard and when the owner removed them, saw overheated areas in the fiberglass
The #1 concern for solar panels
on a boat is shading. You must mount them as far away from possible shading from booms and rigging
as possible. A tiny amount of shading can reduce your solar output to virtually nothing.
The #2 concern is efficiency, since you have limited space, you need the most efficient panels you can afford or find. Smaller 100w panels might be easy to fit, but larger panels in the 280 to 300w+ range are more efficient per square foot.
A technique for maximizing solar harvest is using 1 panel per controller. This way, if any panel gets shaded, the controller can adjust for max. output from that panel while the other panel is also getting MPPT from it's controller. If you connect 2 panels to 1 controller and 1 of them gets shaded, the MPP of the shaded panel might drop to 25v while the MPP of the other panel remains at 29v. There's no way to have 2 different voltages on one cable, so one or the other, or both panels will be at the wrong voltage, depending on what the controller does.
Let's say you have room for 2 x 300w panels on an arch over the stern of your boat and wire each of them to an inexpensive ($100 or less) quality 20A controller. They will take up less total space than 6 x 100w panels due to less border area and less framing in addition to higher efficiency. Each will always produce max. power for those conditions regardless of which one gets shaded by how much. If one dies mid passage
, you still have half of your output. If you kept a spare $100 unit in the box, you could replace it underway and still have spent less than the $500 or $600 or more that a 45A or 60A big name brand controller.
You can get Renogy, Victron, Eco-worthy and probably quite a few other controllers all in the roughly $100 range each. If you mount the panels fore-aft, you might get 3 or 4 panels on that arch, for 900 or 1200w of solar power. Those are rated values, you'll see less than that in reality.