tuffy72561, no, at this point I have not yet used the double double versions of TEO Audio cables. There has been some discussion between myself and Taras about sometime soon trying them.
I would expect that the performance of the conjoined cables would be superior to that of the same cables with splitters. While splitters degrade the sound significantly, the Schroeder Method is so beneficial that this overwhelms the use of the splitters. But, take the same cables without the splitters; I'm sure that would be a nice advancement. I know that TEO continues to explore this and wants to do so with several models in their line. Taras may wish to comment.