It's not really a dilemma tbh. We have to be pragmatic. We already have 6 points. Tottenham has 0. As does PSV. The goal is to qualify, thus getting a point in both barca games will be ideal and put us at 8 points; a strong position to qualify, needing probably just 1 win from the last 2 games to qualify.
Parking the bus is the right strategy. In Nou camp, it's with a measured and conscious effort to watch the numbers we pour forward when we counter. I wouldn't push more than 4 players in a counter attack, with 1 of the 4 players in a 'transition' position and at least 2 getting into the box. They key to barca is not getting too excited on the counter and leaving too much space for them to then re-counter.