It’s flexible. You want to protect Wake and Guam enough that Japan has no realistic chance at taking them. Even falling back to Wake if needed. If you start this out on J1 because Japan allows it and then they turn and go 100% against you, then yea, you probably would need to buy a destroyer and all aircraft for their scramble ability. If they ignore you for a time and go to India, then you could do it for less. Basically, I see them spending 38-41 ipc/round in the Pacific on the cheap side. Some rounds they may spend more if the player sees it fit to do so. The good thing about this is that once the war bonus kicks in, it may give you a chance to split your income almost 50/50 so that you aren’t totally ignoring either theater.