This is where I bought mine. http://www.uscomposites.com/
I've ordered from them a couple of times w/o any issues and fast delivery....but they're only 150 miles away.
I can't think of any reason why you can't support the cross beams, and then pull the hull from that side. I'd buy a tube of anti-sieze grease to liberally apply to the bolts when you put it back together (hopefully you can get it apart )
Use PVA to seal it off so it can dry, or use Pledge furniture wax. I opted for the PVA as it was water based and easy to remove, and won't cause fish eyes if you have to shoot another coat. Wet sanding with a block is a must. You want your final grit to be 1200 or finer before you buff it all out. I wouldn't worry too much about color matching. In time the sun will take care of that if you still have white hulls.
My situation was a little different. i just raised one hull at a time and shot them while I layed on the ground. There's some tape tricks you can use to help eliminate a hard tape line and allow you to feather the finish in. Flipping the hull, really would be best though. One thing about gel coat, it's almost impossible to get it to run, so you can build it up really thick before you hit it with the PVA sealer to set it up. The bad thing is you can blow little bubbles into it as you shoot it, which will make little pin holes when you sand that you then have to fill.
You can also roll it...