Thanks to the required blocks being labelled in the most recent PKHeX commit, I made a plugin to change the overworld Vivillon spawns. It can be found at https://github.com/foohyfooh/SVivillonPlugin and you can go to the releases page for the compiled dll.
This album contains all the Secret Base QR Codes for Pokemon Omega Ruby and Alpha Sapphire that where distributed by GameFreak.
Different to the regular Secret Base QR Codes from other players these bases will appear in the house with the locked door south of the Poke Mart in Mossdeep City.