After I finished my 8 wt. I anxiously bought an 8 line and was set. So I'd hoped. When I showed the rod to a fellow at a fly shop for his apprasial of the rod, he used several lines on it and determined the best performance was a 10 line. Had I waited I would have bought a 10- wt. line from him, but I guess I was a bit greedy. Last week I found a discounted 10 forward weight line and am putting it onto the reel. I don't have any problems doing so. However, my 6 wt. rod has floating, forward weight line in dire need of replacement. My easy answer was to simply install the 8 wt. line on the 6 wt. rod. What are the expected minuses or problems I can expect from doing so? This is a St. Croix Pro Grafite that should be rated fairly close to its intentions, where as the blank was advertised as an 8, which the shop admitted might be conservative. I'll await your answers. JGW