Captains never do walkarounds on 3 crew aircraft, and never in the rain!
A word of advice to copilots- never trust a Captain's TO performance calculation! Always do your own. Don't ever let him point at a number and say 'that's it!'. You can guarantee he will be looking at the wrong page! I used to be proud of my TO calcs. When I got promoted, it must be the weight of the extra ring on the shoulders that takes the blood from the head, but I started making balls ups, and now copilots zap through them in half the time.