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
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.