Adding a panel won't help at all, if it is in the shade!
For the lowest cost, getting them out of the shade is the most important thing.
For a sailboat, as far I can tell, there really is only one good place to put them, which
is as far back behind the stern as possible. So like the link in my previous post, having some super solid arch mount to cantilever them off the stern is needed.
Doesn't having that stuff up there make a lot of really loud noise
in high winds?
I would think it best to make them easily removable.