It depends what level VP you are desiring to push too?
Many skilled players can get to 1300, 1400, even 1500 with all offense and not boosting. I believe the consensus is that is pretty much a hard limit without dropping ice.
Beyond that, the leaderboards are currently mostly blocked off by the cheaters, so not much point trying for global.
The strategy often advocated is to switch to 3 offense and 7 PSC during your buildup phase.
This helps you to stock up PP, as well as get in the practice of clearing your map with limited offense. Then when you are ready to drop the ice, you already know the tactics needed.