Louis,
You're thinking too hard on this my friend! At a max of 7yds you should no problem hitting 99.9% in the 7 circle. I bet you could literally aim once, close your eyes, and complete the "test".
You don't need a laser. Besides, no time limit so just relax and take all day if you need to. If you just WANT a laser because they're kinda cool... (and I think they are) the Crimson Trace or Lasermax internal lasers would be on the top of my list.
Since this will be your primary CCW, any rail mounted laser would be a bit more of a hassle. Unfortunately, "good" and "cheap" are not good combos when it comes to quality laser devices.
My advice... skip the laser for now and spend the money on ammo and range time. Practice makes perfect! You'll do fine
