I think you would have trouble with it, even if the blades fit. Later in the season, you will be drilling through a foot or more of slush, then a foot or two of ice. Without the fluting of the auger body filling the hole, all that slush and ice chips are going to bind up the auger. I fish the lakes around Pinedale and have a 10" power auger. Later in the season, you often have to pull the auger out and kick all the ice chips out of the hole before you punch through the ice. Doing that by hand with a half-assed auger would suck!!
You would be better keeping the 6", and save your money to buy a power auger down the road IMHO.......