Dont do this. I have gotten killed this year betting the under on closers that should be putting up 0's. Tonight - lost on Papelbon (1st blown save of the season) and Boxburger (who sucks i shouldnt have bet that). But, man I think the prices that you get in these situations are slanted so in favor of the books that its virtually impossible to come out ahead even if you only play on really safe dominant guys like Jansen.
The O/U in general is almost impossible to beat vs the books. Just bet on who wins the game. Its way easier.
When you're laying .40 yes it's unbeatable. Alot of books in-game totals are unbeatable because they r greedy thieves. They drive action away with high vig. They prefer minimal action/maximum edge when they should be looking for minimal edge/maximum action.