Okay, so there's an explosion of tactical carbine classes lately and lots of folks are asking questions about which classes are the best, and which one to take.
The US Army and the US Marine Corps offers some great courses. The tuition is free and you'll get to train with the best instructors in the world, but they require a time commitment of four years. That's the short answer. Even the best operators in the world need tune-up skills, which is why we re-train our troops before a deployment. If you really want to learn these skills, see your local recruiter and sign up. The training is the best in the world and you'll train with the greatest people in the world.
However, not all of us are ready for this level of commitment, So, the first question you'll have to ask yourself is: Will I have a carbine readily at hand during a self-defense scenario? If you're not willing to strap it on and have it with you at all times, (and by that I mean in the shower and in the bed with you) the answer is Probably Not. Better you should practice the skills with whatever you'll readily have at hand during a practical scenario. Lots of us forget that running away is a legitimate self-defense skill. More than anything else, you should think about disengagement techniques, staying safe while you run away to a safe place where you can call the police.
I've trained with lots of good folks over my career. The very best. I've never heard the phrase "Big Boy Rules". If you ever hear an instructor use that phrase, run to the nearest exit. Yes, I've been in courses where I ran the course with other people behind me with live firearms. It was part of team training, but the instructors were absolutely anal about muzzle discipline and team fire control. Yes, it is possible to do this safely, but at that stage of training, you are operating as a team who has trained together for many, many days and the members know each other intimately. Still, sweeping a team member with a muzzle is a huge no-no. Don't point your gun at friendlies. Period. This is advanced training, with the emphasis on advanced. A good instructor doesn't want to get to that level of instruction over the course of a simple weekend carbine class. Or a week-long carbine class.
If training is your goal, then train with the scenario that's most likely to present itself. With the tools you are absolutely going to have at hand. Then, keep those tools with you always.
If, on the other hand, your goal is to have an enjoyable weekend with like-minded people, by all means, sign up for a gun course and go have a ball. Make sure that your instructor is safety oriented and remember the Four Rules.