Unless you're a minimalist, and unless you know for certain that your touring will be limited to a few, occasional, overnights, be careful not to buy too small. When I started touring, had no idea it would turn into an avocation, and consequently bought too small. Cost me in the long run.

FWIW, I tour unsupported with Axiom Seymore for kitchen/food and Champlain for tent/clothes, with waterproof covers, plus a rack pack for sleeping gear. Great to have room for extra food, water, and clothes when needed. Total weight 30-50 lbs depending on the season and route. Extra weight is really not very noticeable.