dr_insaneI think my main question is being misinterpreted. I'm not asking for preferences on sensitivities, I just want to know if keeping my sensitivity/dpi/360 the same for every single class will be beneficial in the long run if I get used to it?
In my opinion, yes.
If you have different sensitivities per class, for example, that's NINE different muscle memory you need to build up. Like at this point, you instinctively know "if I move my mouse this much, my crosshair goes this much" but with different sensitivities, you're going to have to do some extra of "Okay, for Soldier, if I move a little bit, I do a 360...okay for Scout if I move a little bit...I hardly move at all", etc. In your situation of hitscan and projectile, that can also throw you off. "Okay, my Rocket Launcher is out, I can do easy flicks with little movement...okay I took out the Shotgun, now I need to move my mouse A LOT to kill that Scout".
So in short, yes same sensitivity because it's just one thing to get used to. In the end, as long as your sensitivity is COMFORTABLE to you, then go crazy. If you have to really hurt your wrist to play Soldier or whatever, then that is a little concerning. Of course, if you decide to have a different sensitivity per class (or in your case, per hitscan and projectile) it can still work as you will eventually develop the muscle memory for the different types of weapons, but I personally recommend staying with one comfortable sensitivity.