I think you don't understand the problem. If you can cast the flies you want to use with the line weight you have, you are OK. The lighter weight rod will land the fish if you use the butt of the rod to fight the fish, not the tip. I've caught a lot of steelhead on 6-1/2 to 7-1/2 ft, light rods and they work fine as long as you can present the fly, and that depends more on the line weight. Review a few old tapes of Lee Wulff landing big atlantic salmon on his favorite 7-1/2 ft rod and you will feel better. The reason we use an 8wt rod for bass is the size of the fly, not the fight!