Follow the AFM/POH recommendations. If it says full flap, use full flap. However, to allow for other variables (windshear, etc) you may elect to use less flap or a slightly faster approach speed. But be careful.
The 150 with it's little Continental isn't best known for it's power output, and with carburettor heat applied, engine output can be significantly reduced.
My advice, if you're nervous or not sure about the 150, practice landing the aeroplane in various conditions on a longer grass strip until you are confident and/or proficient enough to try the 450m one. Try going around at a sensible height to see how it handles for yourself.
Kermie
