Audioquest Slate biwire vs Audioquest GBC single wire


New to Audiogon. I just purchased here PSB Imagine T2 speakers, driving them with an Arcam Alpha10.
I need at least a 20' speaker cable pair, but have a tight budget (no more than $250).
I have seen for sale elsewhere used Audioquest Slate biwire  cables, 23' and 21' lenght, bananas on both ends for $149, but also used Audioquest single wire GBC cables, 25', spades at both ends, for about $ 100.
Have not been able to figure out which are the better cables. The Slate cables are older, i believe.

I'd be grateful to hear your opinions or about references i should check.

Thanks, Manlio
manlio24
GBC is a 6 conductor 12awg.
Slate is a 8 conductor 12awg.
I suspect that Slate is going to be better because it has one 20awg Perfect Surface conductor. GBC only uses LGC long grain copper conductors. I looked at those slate bi-wire. It appears that they have the silver plated bananas, so keep that in mind if you are critical about termination type. Long lengths don’t come up for sale too much. If you’re patient, you may be able to get a Audioquest Bedrock (which is better still).
Buy a pair of Anti-Cables from Paul Speltz! No need for bi-wiring - no significant improvement over regular hookup!
I have a 25 foot pair of Slates I was using a few years ago.  They seemed to emphasize the bass while slightly rolling off the top.   Not in use any longer.  
Thank you Auxinput for your input( ...). I am fine with bananas, but both amp and speakers have gold plated termination. Does that not work well with the silver plugs?
And stereo5, thank you for your feedback as well. the PSB Imagine T2 may use a little emphasis on the bass. Do you think that $ 149 is a good deal?
There's no problem with having gold-plated binding posts on amps and speakers.  Pretty much all posts are gold-plated anyways.
Silver plated bananas will increase the resolution and attack of the sound.  This is good if your system is very warm/slow sounding, but you can easily cross that "fine line" into the "too fast" area (depending on the resolution of your current system).  If this happens, the music becomes too bright/harsh and can actually sound a bit sterile/artificial.  It is just a matter of experimentation with your current system.
oh, $149 is a good deal, but you can get this pricing a lot.  Lot's of people sell older Audioquest speaker wire for good pricing.
A set if AQ GO-4 used should be close to your target price. If you can wait, check Hifi Shark. If not check Hifi Shark for the Slate.
Bob
The Audioquest GO-4 uses much superior copper than Slate or GBC, but it's only 4 conductors and 15awg total.  The Slate uses 8 conductors and is 13awg.
Thank you all for your feedback. 
after so much hand-wringing I made an offer for the Slate cable, but i have not even received feedback from the vendor! so much for that!
stereo5, would you be interested in selling your Slate cables, if you still have them?
Again , thank you all and cheers!
I found a 10' set of new Rocket 33s relatively cheap on Ebay after a chance meeting with Bill Low at a shop...I was using Type 8 that I'd made into a biwire cable, and he pointed out the advantages of the "magnetic isolation" of Rockets...he was right as they work amazingly well. Thanks Bill.