Seeing as I haven't put anything up for a while...
This is the way I work. I do a small rough about 80% of the printed page. I like working small as it seems easier for some reason. You can eyeball the whole page so prportions are easier to keep in check. Perspective at this size is simpler too as the vanishing points don't have to be so far away.
I then scan this into the computer and put the gutters in. On this page I moved one of the figures over in the middle panel too. I'll often scale up certain panels or move things around at this stage too. I then convert the image into a light blue colour and print it out artsize on the board. Really after this I should go straight to the inking stage but instead I mess about tightening bits up so it's less likely that I'll make mistakes in the inking.