The payout structure means you're absolutely playing for first place so I would say once the blinds get meaninful to start raising every time you think you have a shot at the pot. Most important thing to observe is how strongly the players defend their blind, starting at your left and going around. You're gonna need to win every pot you can, and hopefully these chips will give you a buffer for when you wind up all in (which will hapen several times and is unavoidable). Most importantly, make sure you win yu're coinflips.