You do need a flashcart for the simplest method if above 11.3, but you are on 1.0.0, you shouldn't even be worrying about such things! Anything between 9.0.1 and 11.3 will work fine for you and get you CFW. Why are you so insistent on doing the all firmwares method? The soundhax method works for all version between 9.1 and 11.3 and if you are between 9.0.1 and 9.1 you can instead just replace soundhax with browserhax and still install CFW without a flashcart.
Using TWLoader you can already play almost all decent or above games without any issues since it has quite a nice compatibility. As for upgrading and downgrading, what is even the point? Only reason to downgrade is if you want GW, which isn't worth it and you can just stay on last update just fine with CFW, so I don't see how that's even gonna justify the flashcart... As for the not caring about FW he has, flashcart compatibility can be shaky unless he gets a really good one. But yes, his choice, but a simple game to update is easier since you can find games everywhere, unlike flashcarts.