Injuries off I assume...
PAs don't change across low to mid caps. You can squeeze by with 4800 to 5000 if you bat pitchers first. Otherwise ~5300-5500
i have used 1100 ip at $40M without an issue but my defense was great. At $80M, I think 1350 ip might be about right.
Keep in mind this all depends on the extent you can split you squad an allow a hand full of players to fatigue.