Would this be a place to start learning:
LEARN TO BUILD YOUR OWN SOLAR CELLS PANELS DIY KIT | eBay
They are 2/2 not 6x6 but I'm thinking it might be enough to learn on.
I see many panels are 3 x 6 is that OK?
What about these?
108-3x6 solar cells manufacturing grade cells with wire kit and leadbox(A grade) | eBay
Do you have a link for the panels you used?
How do you choose.?
Are you using any encapsulant?
Did you sand the clear gellcoat?
If not how did you get it smooth?