I think "Delaware" is indian for 'river of constant friggin wind'.
The short answer is: Use a 6wt.
I think you're going to find that most of the fast or ultra fast action rods designed for distance suck in close or require you to overline them at shorter distance or it's just too much work to cast with any accuracy at 20'.
Which 5wt is best for up there? Good question. I've seen guys use 9', 9.5' and 10' rods to fight the wind or to cover the required distances. You'll get the NRX, One, BIIIMX and other suggestions. Without casting one, don't purchase. I've cast Z-Axis, One and TCX. IMHO, none of them are great by any means but the Z is what I ended up with. Since 95% of my fishing is on the Big East (or on WB if I have to), it's a similar situation but probably a little more wind involved. The line up of rods consists of a St. Croix Legend Elite 905-4, Z Axis 905-4, Sage RPL+ 906-2, Save VXP 906-4, TFO Axiom 906-4, Redington CPX 10' 5wt and St Croix Legend Ultra 906-4SW.
When floating, I'll have a 6wt rigged with a larger fly / heavier tippet (#10 March brown on 4x), I'd also have a lighter rod rigged with a longer leader and lighter tippet (#14 Hendrickson on 5x). I might also have another dry rod rigged with a longer leader yet and a smaller fly (#16 harrops caddis emerger on 5x). That permits quick change w/o screwing around with leader, tippet or fly boxes. If you are on foot, not such an easy task to carry multiple rods (also known as PIA).
A 9' - 9.5' rod should be good for length. You can then choose a 5 or 6 weight model. Some rods will allow you to carry a spare spool in the vest and change from 5 to 6 line if the wind kicks up. The extra line weight will allow you to more easily get the fly to the fish in a breeze. On windy days up there, you have to pass up on fish, put yourself into a more wind friendly position on said fish or find areas that are sheltered from the wind.
I'll agree with the report you've gotten on the One.... it felt too firm all the way to the tip for my liking. I prefer a fast rod with a bit of a softer tip. The Z Axis felt too soft into the butt and mid section but it's a pretty good rod. For my personal preference and casting style, the Legend Elite is money and the ol' RPL+ isn't too far behind. The Axiom is similar but a little more stout. The St Croix retails for $450 and the TFO retails for $279 so you don't have to wrap up $700 to get a decent rod. Also, the TFO warranty is crazy good. Last trip up, the tip on my St Croix broke....$30 and spare tip arrived at my home in 3 days. Also a nice touch.
Not sure where you're located but the offer is there to cast what I've got on hand. Lines range from sharkskin to Rio Gold to Rio Perception. A line change can dramatically change the performance of the rod.
Whatever you do, make sure you cast as many rods as you can before making a decision.