Red Hawk=G2+CoA.
Red Roc=G3+AdvCoA.
Nah I think it's a bit different and
@sanjikun has it closer. Just look at the names:
- Base Luffy: No special names. Adds "CoA" prior to Gum Gum Pistol when using CoA (luffy doesn't have a special name for CoA in base form)
- Gear 2: Adds "Jet" to his moves. Adds "Hawk" to his CoA moves. Adds "Red Hawk" to CoA moves that are on fire.
- Gear 3: Adds "Gigant" to his moves. Adds "Elephant" to his CoA moves. That's it
- Gear 2 and Gear 3 together (or compromise): Roc Gun, a CoA version of "Hawk" moves. "Red Roc" is a CoA, fire version of "Red Hawk".
- Gear 4 gets weird with names. but as mentioned before Kong Organ and Kong Gattling both exist so there are speed variants to even G4, same as there is also size variants with Kong Gun and King Kong Gun. Snakeman makes it more complicated, because it adds "Jet" again to certain moves like Culverin, which becomes Jet Culverin.