I prefer the Mossberg type thumb safety but I had the flimsy plastic Mossberg safety replaced with solid metal ones. The downside is that Mossberg recoils more than 870 due to lighter receiver.
On 870, I have the VCS jumbo safety.
I would recommend shortening the stock(wood instead of plastic) and thinning the grip area very slightly and having Pachmayr Decelerator pad installed for faster mounting/more comfort.
I find shorter LOP (around 12.5") much faster to mount than the factory LOP(I'm 5'10"/170lb/medium hands/long arm but look lighter than actually is).
I would recommend the following type of drills:
OFF THE TOP OF MY HEAD BASICS said:
- basics: bring the gun to your LOS(Line of Sight) once you acquire the target and don't move your head, and shift the focus from target to front sight(don't worry about the waver(even Olympic class shooters waver) but focus on maintaining LOS(Line of Sight) PARALLEL with LOF(Line of Fire)/bore axis)
- making the correct mount(toe of the stock in the shoulder muscle pocket) natural and consistent, even in low light condition
- learning to assess(front part of shotgun slightly lowered for better visibility to observe your surrounding unobstructed) and bringing the shotgun to point of aim lighting fast(instinctive) when you see the target
- ability to turn left/right/180 degree back w/o sweeping those around you
- ability to bring the shotgun to target naturally even going from standing to lying on your back(like when pushed/tackled and you fall over)
- ability to shoot the shotgun naturally in kneeling(both left and right side), squatting, sitting, standing on your knees, etc.(you can't always choose your position and you want mobility/utilization of cover maximized)
- ability to maximize usage of cover for both strong and weak side(this is where I see weakness in competition shooting(quite often, exposure can be dramatically reduced))
- ability to shoot on the move(bent knee/shock absorber technique)
- ability to shoot with weak hand, using strong side eye/shoulder in case strong side arm is injured, and vice versa(this is one instance where pistol grip shotgun is much easier to do although it's still doable with regular stock w/o being a weight lifter)
- shooting when moving backward(shuffle backward, feeling the way back with your rear leg as you move backward and shoot)
When you shoot, you want to be as unemotional and relaxed as possible, like cutting a slab of meat that you are going to cook for dinner. When you are tense and all bunched up, you are basically fighting against yourself and is being inefficient in the worst possible way(slower reaction, poor mechanical efficiency unless you are a caveman swinging a club, LOL).
Shooting is a fine motor control skill and under stress, fine motor control skill goes downhill and gross motor control skill takes over, increasing group size by as much as 40%.
In movies and TV, shooters routinely expose themselves and is shouting and is super emotional, but in real life, that's not the way to go. You want to shoot/fight as if you were cooking and/or going about daily, routine task.
You want your moves to be unpredictable(depend on mobility but don't be consistent about it because then your opponent can time you and anticipate your moves) and maximize cover as much as possible.