I fly a pa28-161 and also use 3 stages.
Using full flap has a number of advantages, it will give you a steeper angle of descent, which imo allows you to control the height better (better view etc) and it will also give you a shorter float. Unless there is a specifc reason to not use 3 stages then I have always used full flap to land. The only down side I can see is that if the engine should fail then you would have a bigger rate of descent then if you had 2 stages.