hi proprider
Nice work :)
I noticed the stringers too. Ginge is correct. Those stringers would be better if they were scarphed. 30 degrees is not enough taper. That is closer to a butt joint than a scarph. You should be looking at a taper of 8:1 for your scarphs. i.e. if the ply is 20 mm thick your taper should be 160 mm long.
All is not lost though. Put "fibreglass butt straps" on the butt joints by laminating some unidirectional along each side of those joints when you encapsulate them with glass.