Front Sight Adjustable Iris Sizes ?

[Northwoods308Shooter]

Long time smallbore competitor, recently took up Mid Range , Long Range and Palma,......I'm thinking of switching my my front sight from the 22mm Sinclair Ladder , to the Centra Goliath 30mm and a new adjustable iris, but wondering what size range would be best to go with for those games, any suggestions ? without being able to look right at this second I believe my 22mm has a 2.8-4.8 and that seemed to serve me well so far in my young highpower career, and I've been happy with the sight pictures, but wondering if a different range is better for what I'm shooting and those target sizes ?

C.D. gun)