Smaller gauge?

I just found some cones of wool in my stash that are really talking to me. Trouble is, it's fingering weight, so I'd have to dramatically alter the gauge (and if I did, I would attempt it on my machine, not by hand). I have 2700 yards (500g) of black and the same amount of cornflower blue. I'm thinking of making the sleeves blue and the bodice black, but not entirely certain I want to do it by machine. Hm...

(ETA: The brand is Schaffhauser Wolle Lamb's Wool.)