Screens are a bit of a personal thing, one type doesn't suit everyone. Depends how tall you are, where you sit, what helmet you have, how fast you ride etc. I'd experiment first with whatever you can find (like card) taped/cable tied to the bike to see what your going to need (or borrow someone else's screen!) I've used old estate agent's for sale signs to cut up and experiment with in the past - which worked a treat!