Much has changed over 2021 in the Coffin quiver of fly rods. I have built many, sold some, and gifted some. For my quiver it's a never-ending "task" to fashion a complete set of fast graphite weapons for any water I am likely to approach - that all look cool AF and perform similarly, meaning they are Rodfather custom rods I've made. I fear though that I am there. I have go to entries (shown in green) for rods from 1wt to 6wt and many have manufactured backups (shown in blue) if one were to be out of rotation for repair. These are augmented by several specialty rods in addition, all Rodfather versions (shown in red). Specialties include: a two-handed micro-spey rod, a euro-nymphing rod, and a 10' 5wt mending demon rod, and finally the un-special super-special rod, the Rodfather Colorado, an ultra-cool universal use ERN 6 weapon that can do anything from small dries to heavy nymphs to big streamers all on the same day. But how do I know these things in advance of field trial? As to weights in hand, and swing weights, my rods are a skosh heavier than manufactured rods (of the same line number) - but cooler and often more capable. Anyway, that's the current lineup as we bridge years. 
All this above is well and good. Yet, in addition, I "like" fly rod kits that are balanced well (center of mass) to the front 1/4 of the handle where my index finger acts as the fulcrum on casts. And I "like" rods which have a tip action angle of 68°-72° 'causing those to toss the line sweetest and truest. And I "like" lines very well matched to a given rod's power, for distance. But why? I am a guy who believes true objective measurements of physical systems
capture expected performance... there is no "feel" or "what you like" in
being the best or optimal. I know I am missing a measurement of
fly rods (systems really ~ meaning including reel and line) that can lead me to a
more complete definition of objective performance... that is swing
weight. While I know the total weight and balance points of my fly rod systems (and that is not shown in the graph above at all, though I do have it elsewhere) it is extremely important but insufficient. I
want to capture the effort needed to cast optimally with a properly loaded and well balanced system
objectively. I know absolutely from experience that some comparable
weight and speed rods which are "properly" balanced & loaded are "easier" for me to cast. I will ignore line slickness and guide sliperiness for the time being and only use smooth variants of the same SA lines in measuring. I am approaching my next measurement step as a static mechanical measurement, despite knowing the system is fabulously dynamic. I am studying the
physics and ways to measure swing weight but have not yet landed on an
acceptable static model. Too, I need it to be simple... as ERN and AA are simple objective measures for fly rods which immediately provide the exact line weight line you should buy to load the rod well. I will also delve more deeply into balance and the need to buy the right reel (just weight-wise) to make carrying and casting "likable," aka the least effort. This is all research and, of course, measurements, for next time.
