Re: Phaser banks on the Constitution class
From Memory Alpha
The Enterprise's three double phaser bursts, which Sulu says constituted a full discharge of phaser banks, fire from an unusual location in this episode – not from near the glowing dome at the bottom of the saucer, but from much higher up, closer to where Matt Jefferies originally located the main phaser banks in his early diagrams of the ship.
That's correct. According to the diagram in The Making of Star Trek
the "main phaser" alligns with the uppermost "ring" at the bottom of the saucer. It's a fascinating prospect that the TNG design might have originated from a mostly unvisualized idea of Matt Jefferies.
"The first duty of every Starfleet officer is to the truth, whether it's scientific truth or historical truth or personal truth! It is the guiding principle on which Starfleet is based! Jean-Luc Picard