Ehhh... Why don't you just take your gun model (with or without player's hands), and use code to set it off to the right side of the screen? Then make the crosshair stay dead center the whole time, right in the middle of the screen. Then your gun model/hands pan with the camera everywhere you look. That's how it's done in almost every fps game. Watch some Youtube videos of other fps games, and you'll see exactly what I mean...
To make things easy, if you don't want to use any Trig to calculate the y-axis distance the gun has to stay from the center of the screen, you could even use vec_for_vertex, and set a constantly updating vector from a vertex on your character model. Then you just add or subtract the offset from that. This is pretty easy stuff, bro. If you don't get what I mean, you should really check the manuals and do the Lite-C workshops. If you prefer C-Script (yuck), you can easily find hundreds of tutorials on that.
