What's in the 2 80s? One with trimix and one with o2 or 'shallow mix'?
Assuming your deep bailout is different than your diluent, you would likely have either 21/35-ish or 18/45-ish for your deep bailout and 50% for the rich mix. Different people and instructors feel differently about the PO2 max of bailout at depth (and certainly, how long you would be on that mix -- e.g., penetration).
If you are on a unit that uses the same gas for Diluent and Deep Bailout (e.g., the popular Choptima with twin LP50s for bailout/dil), then it might be different.
I have no idea what the agency standards are and don't teach so take it with the proverbial grain of salt. But, generally, for most MOD2 (60m/200') dives I do, I feel comfortable with two bailout cylinders with 70-80 cf each.
Your instructor should definitely prep you for gasses you will need based on your unit, dive conditions, etc.
- brett