I didn't get how you would make 10 to 20 million credits per hour. You made 2 mil on that one mission. At best I could imagine you doing 3 missions in an hour.
Also, you didn't mention scanning the nav beacon. Isn't that the first thing you should do?
What about missiles and torpedos?
I'm just asking questions. I'm looking into getting into doing some of these missions. But last time I took one, it cost me. My first attempt I got killed. OK, I was rusty but some of those pirates are mean. In my second attempt I killed the pirate but then he respawned magically and killed me. Have you ever encountered 2 pirates with the same name spawning in the same instance?
If I take one mission at a time, it takes about 12 minutes round trip. At 2 million a mission that is 10 mil. I can sometimes grab multiple at a time, which speeds up the process (on average I go out with 2-3 for the same system, for about a 15 minute round trip). You also didn't account for the bounty value, which adds another ~150-200k (value depends on size of the pirate ship) plus the Kill Warrant Scanner which adds significant value (50-100% more bounties - I still haven't quantified the exact value since it becomes very complex with the KWS to attribute cash for each kill).
These values are allied with the faction(s) and dangerous combat rank. The major affect to mission payout is the minor faction rank (allied with the minor faction gives max payout).
Scanning the NAV beacon is no longer required in 3.3, since all ships are equipped with FSS and Discovery Scanner.
I am planning a video that discusses weapons in detail. Missiles and Torps are definitely good weapons (especially missiles), but the torps have VERY low ammunition. I wouldn't take Torps without Reverb Cascade. Missiles are fine, engineered or no.
I am also planning on making another video where I use a smaller, cheaper ship to take down a big pirate.
Also, there are occasional bugs where the pirate will respawn, but you can just high wake away back to your home and complete the mission, since the first kill counts.