I have a MAS 15x6 on my Saito 1.00 in my H9 Spitfire and she'll hold still on the ground and fly like a bat outa $%^ when prompted. I just got a Saito 1.25 for a WM Super Sports Sr. (a 9.5 lb sport plane) and will be using a APC 16x6. I wish I had results of that for you but I have read that is a good match for the 1.25... Sorry I do not have anything as big as your 1.80.