Help me choice Audioquest speaker cables

The Rocket 88 is a very good cable that represents a "sweet spot" of sorts for price-to-performance. Even on a modest system, I heard a big upgrade from 88 over Rocket 44 (both single biwire configuration, both modern versions, to be sure -- since Rocket production goes back many years). It's a good cable you can stick in any system in need of a good cable, and get good performance.

Above the 88 is where it gets tricky - system & preference matching becomes key. I've had my share or exotic older AQ silver cables (KE-4, Kilimanjaro x2, Everest x2, Wildwood x2, Thunderbird Zero). Sometimes, in some systems, the silver cables simply run away from 88's, revealing a large chasm of difference in detail and dynamics. Other times the 88's hold their own quite well; their natural warmth can actually be quite seductive. The Thunderbird Zero didn't do it for me -- I think, as they say, these really need to be the biwire version to show off. I wouldn't recommend just using the Zero as I did. AQ recommends William Tell bi-wire over Thunderbird Zero alone, and I believe them. 

Better off changing a few capacitors and resistors as cables can vary depending on your components especially if you buy and sell them at various times.

I compared AQ Firebird speaker cable combo with AQ William Tell (Silver) speaker combo ...

Nice to know.  My next speaker cable change/upgrade will be from copper to silver like my interconnects, so I was debating between these same 2 cables models.  Probably go for the AQ Dragon or VooDoo PC upgrades someday also.  The AQ Dragon speaker cables, not within wallet reach but there are other toys...

I decided to hold off on 4ft speaker cables because the AQ WT silver combo including 20% discount new, will run me $6598.92, a bit too much right now.

Please note: During our two month loaner trial on a pair of AQ 10ft Firebird Combo (I only needed a 4ft length).When my rep. returned the cables, they were informed one of the pair plastic termination caps (where the termination divides into 4-connections) was "scuffed" and they wanted my rep. to pay for this. I don't know how it turned out but what a surprise for what was suppose to be a "loaner cable" (keep in mind they sent their second most expensive cable especially at this length) and I assume "New". Bad experience for my AQ Authorized Representative. 
 

So, you were looking at cables over $10K, jacked up a loaner set that you had for 2 months, and now balk at $6k? I feel sorry for your rep and dealer. 
 

Some advice that someone should have given you already: your overall system would benefit a lot more from better speakers and amps than it would cables. Just recently I had your same setup, and it’s “meh”. You’d be MUCH better off investing that money into better components. Given how narrow you have them placed, 800s are far too big if you don’t have more room for them anyway. Go for higher quality smaller speakers and a sub. There’s a set of MBL120s and a MBL amp on Audiogon that would mop the floor with your B&Ws.