Defiant Lakota was a very brief visual fight. A couple of cheap shots on Defiant, Defiant makes a two passes. One pass over the saucer and another over the top. We never get the rear approach so it's hard to say but Lakota had a bunch of extra phaser arrays where there are none on the moldel such as on the neck, between the impluse engines one on the pylon junction...
We're not sure if the Defiant passes behind and below the Lakota, but she does pass above from from front to rear, IIRC.
The entire fight lasted between 4-5 minutes, of which we only saw the early portion. In the exchange:
Lakota lands 10 phaser beam hits (100%) attempting to target weapons and engines.
Defiant lands 33 phaser pulses out of 52 pulses, 2 phaser beams and 1 photon attempting to target Lakota's weapons.
What we also know is that Lakota's phaser beam takes 20% off of one of Defiant's shields and the battle goes long enough for them to hit the ablative armor. Lakota as far as we know did not use her photons or quantums.
At the conclusion of the battle, neither the Lakota or the Defiant succeeded in their goal.
Miranda's Roll Bar Phaser did CONSIDERABLE damage to Enterprise. The bolts were twice as large as Enterprise. And Reliant was firing at full power. But we know Enterprise was not because they lost main power. Even the Diagram shows Relaint hit a lot of locations and did considerable penetration. That's to be expected because physically those roll bar phaser are 2 or 3 times larger than the banks both ship use as standard armament.
Miranda has two aft torpedo tubes while the Enterprise has none.
The Reliant has two "unconfirmed" aft tubes since we only see one torpedo fired. Is there a tv episode where we see both in action or a close-up?
As to the phaser power, they were fired at low power. You can see in the screenshot that none of the power indicators are lit up to the left Joachim's hand.
Also, none of the phaser shots (or torpedoes) penetrated more than a room or so into the Enterprise.
At most they were at 1/4 phaser power.
Remember, full power phasers at medium to long range in "The Ultimate Computer" killed the entire crew of the Excalibur. At point-blank range, full phasers would've cut the Enterprise in two, blown large chunks of it into oblivion and probably set off the antimatter fuel resulting in the biggest explosion that side of the Mutara Nebula
Not to mention Khan would've FAILED in robbing the ship of power and taunting Kirk since he would've been killed with full power phasers
