I think there are more Rank-Up Spells than you need. They might end up becoming dead draws, so you can use a few of these cards to help you get Rank 4 Monsters:
Photon Thrasher (or Slayer, the Level 4 one). You can simply Special Summon him from your hand if you control no monsters, he also has a good ATK, and is a LIGHT monster. After you summon him, you can use him to get rid of pesky monsters, such as Rai-Oh, or just summon another monster for an instant Rank 4. I don't think you'll need Gawayn after using this guy.
Goldfish and Goblindbergh are Ok, but there's always the risk of being hit by Veiler. Running Kagetokage avoids that, and he's also searchable by King of the Feral Imps, another Rank 4 monster. You can also run Summoner Monk, since you have a lot of Spells in your Deck. He can summon any Level 4 monster from the Deck, so he'll help you a lot with Xyz.
The ammount of Rank Up spells is up to you, but 3 of each is way too much.
For the Extra Deck, you could include King of the Feral Imps (for Kagetokage), Master Key Beetle, Gagaga Cowboy, Maestroke, Abyss Dweller and Paladynamo.