Dracovish is technically the best fossil.
It is also a water type, meaning it does 2x damage to Charizard.
But I would prefer Dracozolt, flying type attacks do 1/2 damage to it, while fire type moves also only do 1/2 damage to it.
I would never use Arctovish due to the fact that Leon's Charizard has Ancient Power, Actovish is also really bad in my opinion.
Arctozolt cannot be used since it has 2x weakness to fire type moves.