Kimber Kable 12TC vs. 8TC for 15ft runs.

Anyone having experience comparing the KK 12TC vs. 8TC speaker cables? I require 15 ft cables and am wondering the benefits of the 12tc over the 8tc cables run between my BEL 1001 MK5 and Esoteric MG10s. Thanks in advance for your help.
I am wondering the same thing except I need 20 foot runs. Do you know what is the gauge of the 12tc wire? I am using 20 foot runs of Groneberg speaker wire but not sure of the gauge.
12 tc is 8awg, and 8 tc is 9awg
I was considering going to a pair of 12TC, but went with a second run to have double 8TC biwiring.
The 12TC is a little heavier than the 8TC. but not much.
The claim is the 12TC has better bass.
With the 12TC internal biwire would allow 4 strand for mid highs and 8 strands for bass.
(or 5 and 7)
I already owned the old blue/black 8TC, so i added the white/clear for mid highs and used the blue black for bass.
Thanks all. I purchased a set of 12TC.