If you notice the OP said 76 seat angle at the beginning, so it's safe to assume the OP is asking what the new Seat Tube Angle will be with a 30mm laid back post.Whatever angle you want. Setback and seatpost angle won't effect the angle adjustment range you get on most seat posts. A 76 degree seat tube angle is pretty average generally too.
You will be able to adjust the average amount of nose down or nose up from level regardless of set back.