I'm looking to buy a shotgun for home defense, as well as just general and overall fun to go out to the property and shoot at various targets. I can't decide if I should get the (1st question) classic full stock, full stock with pistol grip, or an adjustible tac stock with pistol grip. I live in a small apartment so I'm thinking that the adjustable stock would be a better choice, but I'm no expert. It would also be used primarily for general shooting fun at the range and when I go out to the property with the rest of my guns to shoot at different targets set up. I'm leaning toward a Mossy 500 but my real predicament is in the stock type to choose. I'm leaning towards the 500 tactical 6 shot, #50420. If I were to get that, (2nd question) how difficult is it to add ghost ring sights or a rail for a red dot if I decide to do so in the future?