I've read that your 3-bet should be around 4 x the pfr. If someone between you and the pf raiser calls, do you increase your 3-bet to 5x or bump it even higher to 8x if you want to isolate to just one caller? Not 3-betting light here, but for value and isolation. Maybe the best way of asking this is "What's the best 3-bet to get one caller?"