Hiya mate. While I expect there are bigger bags I have no personal experience with them so I can't really comment. I have the OEM ones which are about 20 odd liters a side.
As for the shields check this thread for my perspective on them...
http://www.f6cforum.com/forum/9-honda-f6c-parts-accessories/9370-windshields-my-experience.html
One thing I have learned through that experience is that what is good for one can be a complete nightmare for another however I am pretty happy with my setup now. If I got my jacket open I don't puff up like the Michelin Man anymore but in the rain, well, I'm going to get wet
As for the shields check this thread for my perspective on them...
http://www.f6cforum.com/forum/9-honda-f6c-parts-accessories/9370-windshields-my-experience.html
One thing I have learned through that experience is that what is good for one can be a complete nightmare for another however I am pretty happy with my setup now. If I got my jacket open I don't puff up like the Michelin Man anymore but in the rain, well, I'm going to get wet