yeah i've been in this position, and i usually judge it by what i need. if i need a win, innings or k's i start both, but if the only thing i have to worry about is not getting losses...i suppose i should sit both, but i always end up starting both anyways. so my suggestion is follow my advice, sort of. if it's the beginning of the week, h2h of course, i tend to start both as well. i only bench one if its a mismatched matchup or its a weaker starter.