First Board

I recently moved to the east coast. I have been skateboarding for many moons. I am a functional movement specialist by trade, as in I teach people how to properly move their bodies through full range go motion. I would consider myself to have great balance and coordination. I however, am new to surfing. I am looking to buy a used board, but I am unsure of what to size to get.
I have done some research. I am 5'11", 160lbs, 30 years old.
I am looking for something that I can keep for awhile. I think a foam board would be a good learning board, but I would out grow it soon. I've read shortboards or performance boards would be too difficult to learn on and to look for a fun board, or mini mal. Right now, I found a board thats 6'6", 19" and 2 3/8". Theres another board thats 6'10", 21", 2 3/4".
What are the thoughts on those sized boards? Both priced around $200.
I have done some research. I am 5'11", 160lbs, 30 years old.
I am looking for something that I can keep for awhile. I think a foam board would be a good learning board, but I would out grow it soon. I've read shortboards or performance boards would be too difficult to learn on and to look for a fun board, or mini mal. Right now, I found a board thats 6'6", 19" and 2 3/8". Theres another board thats 6'10", 21", 2 3/4".
What are the thoughts on those sized boards? Both priced around $200.