Actually I have weight on the tail of my Radian to get the CG I want. With the stock prop I had 1 quarter (coin) taped on the tail. When I went to the 10X8 and the 1000 mah pack I went to 2 quarters on the tail. When I went to the 11X8 prop I am running now I went to three quarters on the tail. I think the 1000 saved me about 3/4 ounce as I recall. I no longer have one of the green parkzone packs so I can't compare.