Re: the search for the perfect fly rod???
I think another issue that is coming into play is trying to use the same casting stroke for different rods. It sounds like you have already figured out how a 8' 4wt needs to be cast differently from a 9' fast action 6wt, but the 9' 5wts need a different casting stroke as well. The goal is, if you insist on having a 9' 5wt, is to find one that you can adjust your casting stroke to cast accurately. A 5wt will never offer a presentation quite as delicate as a 4wt, but you should be able to achieve the same delicacy with a 5wt as you do with a 6wt.