Sounds good! The changes you hear would be expected as the speaker axis changes.
Only comment I have is on the power wiring at the battery.
Ideally, the positive and ground connections should be on the opposite ends of a parallel battery setup. This will pull current evenly across the whole bank. Same for the charging wires.
1991 MariStar 240sc, 454, tower, WetSounds, Krypt and Rockford Fosgate