So you want to use the XP 5wt more for just nymphing? In that case I cannot advise on the line differences, I'm the kind of fisherman that changes flies and approaches to suit the demands and conditions so many days I will high-stick with nymphs through pocket water, then switch to wets and dries when the fish begin to rise on calm water.
Like I mentioned above, I was pretty insistent about fishing only my "medium" action SLT 4 wt for dry fly fishing. I'm asking you now, don't shun that 5wt XP to only nymph fishing, you will be missing out!
Thanks much! I'm not opposed to dry fly fishing on the XP. It just that most of my fly fishing for trout is done nymphing, hopper/dropper or fishing dry flys with a dropper. One of my favorites is fishing the Elk Hair Caddis with a dropper. What I really haven't done that much is fish with a dry fly "by itself". Sorry if I was confusing. I love my XP rods. I have 2 5wt and one 4wt. I was lucky and got them all for 1/2 price when they were on close out.