my rule of thumb regarding cabling is this;
Cabling should reflect 10-20% of your system cost.
Said cost can be full retail or used/demo pricing.
The Elations would, in my view, be overkill and might upset the balance of your system. Your system seems to be nicely balanced as it is, and the Fascination is not an overly bright cable. The Elation will be considerably more extended at both frequency extremes and much cleaner sounding (I have noticed that about the entire K-S line), so if your system is tilted to brightness now it might be more so with the Elation. It is a great cable, but it might reveal more about your system than the music it's playing, not a good thing, IMHO.
You're right, the Fascination is not an overly bright cable but it will give me some upper frequency sizzle & snap if the CD or vinyl source dictates it. I'm willing to live with some brightness (not overly) as long as the tradeoff is appreciable refinement.
Also, I switch off with another speaker cable, the Stradivarius from Voodoo Cable. It has a Silver/Copper alloy and is clearly brighter & provides more detail than the Fascination but I like it in it's own way. The Voodoo is clearer & cleaner but the Fascination is richer & more dense with acoustic guitar vs. the Voodoo. Also, both throw wide soundstages. Right now I am waiting to borrow a pair of Voodoo Cable Stradivarius Cremona speaker cable. The Cremona is an upgrade of the original Stradivarius. Refinement is what I'm looking for with the upgraded Voodoo but at the expense of little bit of brightness. The tweeter on the Focus 260 does have some energy but I rarely am fatigued with the sound of it unless I turn the volume up too high. I borrow cables from the Cable Company here in Pennsylvania. They have a wide variety and I have borrowed a lot throughout the years. There is a fee but that amount can be used towards the purchase of cables. Unfortunately, they don't carry Kubala-Sosna cables.
I have had the K-S Emotion in my system for a long time- power, interconnect and speaker cables. The Elation had not been introduced when I bought them. I upgraded one interconnect to the Elation and could hear the difference. However, I think it is probably unnecessary for you to spend this kind of money for your system. The question I would ask is what is it about my system that I think needs to be improved, or changed, and then try to approach that, rather than viewing an expensive cable as a panacea. The only reason I gave you my background is to say that I'm not a hater of K-S or of fancy cable.
While there are plenty of guidelines on how to set up a system, they are only that, guidelines.
I certainly haven't spent that much on speaker cables, though I have looked, and been tempted. I know some fellows who have more money tied up in cables/cords then they do in equipment, but in my mind, that is the lunatic fringe. They seem to be happy though, so I certainly don't object.
Some folks insist on speakers being 75% of your budget, some say cables 10-20%, some say source should be your primary expense. That's why this hobby is so much fun, there are so many paths to audio nirvana.
Whatever floats your boat.