Oh man, I did a grass Challenge as well. You're worried about Charmander? Just wait until it evolves into a Charizard, that's when he gets SERIOUSLY frustrating. Sleep Powder is your friendWell i decided to try a grass mono type challenge on my FR. So, i choise the awesome Bulbasaur, and quickly defeated Brock. Bulbasaur evolved after the battle, and i was happy. Then, i skiped all of the trainers that you can avoid on the path to Mt.Moon, and went back and defeated them with my Paras. After wondering around and hopelessly training Paras, I stumbled out of Mt.Moon, and went straight to Cerlean. I made quick work of Misty, but now i am vastly stuck with my rival. I have no counter to his Charmander as of now.
Anyway, I just restarded my FR and chose Charmander, my favourite 1st gen. starter. After training in Viridian Forest to lvl 16, I beat Brock with several Metal Claws. It would have been a harder battle but his Onix kept missing with the Rock Tomb
Charmander Lvl 16