mediumtext type for mysql migration

I know that the maximum size of medium text is 16,777,215 bytes (16 mb)

I use the following rails migration

def change
    change_column :solutions, :result, :text, :limit => 16.megabytes - 1
end

But I don't need 16mb to be allocation for this results column. I just need 2mb

So will the following work?

def change change_column :solutions, :result, :text, :limit => 2.megabytes end

or will it still allocate 16mb?