This deck is mainly used to duel level 10 Legendary Duelists at the gate so you can summon The Winged Dragon of Ra multiple times in a duel. The purpose of this is to get the Ra playmat by summoning Ra 100 times, and you can summon Ra more than 10 times in a duel, depending on how early you can summon Ra.
The main way to summon Ra multiple times in the duel using this deck is to have your Ra, at 0 attack (by not activating its effect when you summon it), attack into a Gonogo with 0 attack. This is done by summoning a Gonogo and giving it to your opponent using Mystic Box, then lowering their attack using Wall of Disruption. Once this is done, you can use your Ra to attack into the Gonogo without getting either monster destroyed. This will flip your Ra face down so that you can flip summon again next turn, and attack into the Gonogo again to repeat the process.
Gonogo can already be used to protect your LP since level 10 LD at the gate don't have monsters above 1600 attack. Once you take enough damage so that you can activate Destiny Draw, you can summon/set Gonogo to wait until you get Mystic Box and Wall of Disruption. Once you have all 3, use Mystic Box to give your Gonogo to your opponent, and use Wall of Disruption when they attack.
You will first want to use Deep Diver to get either your Ra, or Gonogo. But you can also use it to get your Cat so that you can get Wall of Disruption from your deck. If you already have the main stalling cards available, you can get Cosmic Compass so you can tribute into Ra faster.
These cards are mainly used to return your opponent's card from the grave to their deck so the duels last longer. Discard Tour Bus From the Underworld when your hand is full to activate its effect. Foolish Return and Pot of Benevolence can be used whenever you want.
I can confirm that flip summons do not count for monsters that can't be normal summoned/set such as ojama king and rainbow dragon. Havn't tried it yet for ra, but I thought I would let other people know who want to do that gonogo strategy in the future
A solid (though not as efficient) replacement option is building a deck to send your Ra to the graveyard multiple times and reviving it with trap cards (e.g. various "... Rebirth" traps, Puzzle Reborn, ...).