If all else fails, you can just download Pokemon Piccross from the eShop and install Picchax. This does not install CFW, but it does everything ninjahax can do, and it's completely free and not particularly difficult.
But I have to extract my SD from my N3ds xl, right? I have to deal with the screws and stuff...
Is it possible to use Picchax with the use of Sky3ds without touching my N3ds?