I would have to say 7wt though my first thought was 8wt. There seems to be a big difference to me anyway between a 7 and an 8. A 7wt seems a lot closer to a 6wt than it does to an 8wt. With an 8wt one can cast a fairly decent sinktip if need be but I've yet found a 7 wt that will. But I can't imagine casting an 8wt to a Henery's Fork surface feeding trout with 6 or 7x tippet but I think one could get by with like a Winston BL5 7wt and make it work a bit. I could fish summer steelhead all day with a 7wt and I could fish bait chasing schoolies all day with the 7wt. If one got over his head in a mismatch and the fight is too long just break the fish off. All 8wts have a butt section on the rod but only a few 7wts as far as I know have one. For fish under 15 pounds I don't think you need one anyway. The more I think of it the more we need a 6.5 wt and a 7.5 wt rod. The key is a 7wt will fish a light tippet still handle a good fish about the same as an 8wt. The 8wt just won't fish delicate water or soft fish.