assuming the reeds you want to buy are aftermarket, lean the needle one clip. If its stock 3rd go to the 4th. With airbox on and no lid go up two main jet sizes to start. 4 if no airbox at all. richen your pilot up and happy tuning. You shouldnt need a new pilot with the airbox on just richen it up with airscrew. Huge power difference with k and n over stock. run outerwears and keep stocked up on the recharge kits. I would run airbox lid on with some of the 1" oilable foam inserts. Dennis kirk sells 6 packs of these. Keep em clean and oil them too. The adapter plate you mentioned is the shiznit if you have an airbox.
I live in michigan at 800 feet above sea. 20 over bore, reeds, fattys, k and n pods, no airbox at all, stock carbs. Plug chops are perfect with 27.5 pilots 1 and 1/4 turn out. 330 mains. needle on fourth clip. Runs like a raped ape. no smoke when warm, smooth through all of powerband.
happy tuning