Let me clarify: I'm talking about a portrait-layout, non-OOTS style comic, with about four lines of panels. What I need to know is what size will have people squinting and what size will make people have to scroll across to see everything, so I can choose something between those.
At the moment I'm planning on using 650x800ish, but wondering if something bigger would be better.
I realize this is probably insanely hard for you to judge.