Yes got that. Would be better if you had to stick with one captain per round I reckon.
That's the way we were used to but I suppose it's the same for everyone here. I suspect having negative points in the other FFs played into the minds of many here, when in reality I don't think any player has below zero so far.
You can switch the captaincy between matches, it doesn't have to be the next day. Basically, it's finding the baseline score for a captain that you are satisfied with, or you will continue switching.
You can switch the captaincy as long as your new captain hasn't played yet. Say, you have Jackson Martinez (he's Colombian) as captain and he doesn't do well, you could switch to Rooney for the next game.