Your material stackup is in the range where dimpling (hot or cold) not countersinking will need to be considered if a flush fastener type (i.e. nas1097) is used. If sheets are a combination of different alloys such as 7075 and 2024, then hot dimpling will have to be performed around 525F +/- 25F...
Does anyone know of a supplier out there (not the primes, preferably 2nd, 3rd tier ) that peforms hot dimpling on AL-7075/2024 stackups? Per Lockheed LAC0581, hot dimpling (525F +/- 25F) is required when mixing noted alloys with total stackups from .032 - .071. This is a AOG on the P3 program...