Solipsism seems like something that i could really get behind with a decent amount of consideration. Some very valid points and you're completely right in saying that we're nothing more than matter and that everything is subjective.
One thing i had a problem with was when you said that agnostics think that we could never possibly comprehend the universe at it's fullest. That's not true. Agnosticism, the way i look at it is more religiously centric and that we believe that no god, higher being or miracle can ever be really proven so we choose not to put our faith in things like that. I believe that if we manage to achieve an equilibrium with our universe at some point we may be able to understand literally everything.