Trail Boss is a very bulky fast burning powder designed for "cowboy action shooting" That means it will get the pressure up quickly but to a level closer to black powder rather than smokeless powder (greater than 10,000 psi but way below 35,000). In reality, you can use a fast burning shotshell powder like Red Dot, Clays, Titewad and get the same performance but Trail Boss is so bulky that you also don't risk a double charge in a big case.
2400 is on the opposite end of the spectrum. It is a slow burning powder meant to drive the bullet as fast as possible within the pressure limits of the cartridge. It often does not get 100% consumed before the bullet leaves a pistol barrel while Trail Boss typically is 100% consumed by the time a bullet is about 1" after it leaves the cartridge. The doughnut shaped flakes do not measure perfectly but they are so fluffy, a few +/- dozen don't add up to very much weight difference and even less pressure/velocity difference.
I wouldn't waste 357 magnum or 44 magnum cases with a Trail Boss load if you have 38 special and 44 special cases laying around. The only reason to use the bigger cases is prevention of the "crud ring" when using the shorter cases if you are out shooting both lengths of brass in the same session.
Inexperienced or forgetful loaders (no offense) prefer Trail Boss over a fast shotgun powder because you can easily see a double charge but grain for grain, Trail Boss costs more than the other powders. It may not matter to you but Trail Boss smoke also has a "strange" odor to it too.
Powder coated bullets work fine with Trail Boss or any other powder. You'll see less smoke compared to traditional lubed or tumble lubed bullets