Speaker cable upgrade recs please

Looking for audition recommendations for all who may have experience with similar equipment. I have 12' mono runs of Harmonic Tech Pro 11+ bet. Meadowlark Ospreys and Simaudio Moon W5/P5 power plant. I've tweeked and upgraded sources now to the point I sense a significant improvement yet lies in better speaker cables. Question is, what direction is up? I can budget up to 2k on the used market. I enjoy the clarity of detail, dynamic range, and stage depth of my system, and want to continue to maximize this. Comparisons bet. AZ Absolute, Nordost Heimdall, Transparent MW Ultra, would be of partic. interest, though I'm just beginning research, so quite open. The other big question is, do I benefit greatly going biwire (I'm currently jumping the Ospreys)? Lots of questions I know - thanks for any advice you might have.
Try DNM, but they might be too "cheap" for u!
Thanks Lindisfarne, I'll look into DNM. btw: Though I might try to budget for 2k on this project, it doesn't mean I have to - as I'm sure you well know, lots of xperience w/ this hobby has proven time and again that great sound can be achieved w/o breaking the bank. :)
I am not sure I can recommend a cable for your system but I can let you know my impression of the heimdall. Though nordost has been associated with being "bright", and the Red Dawn really confirms this, I have not found that to be the case with the baldur, heimdall or Frey. I currently am auditioning a pair of heimdalls with a pair of verity audio parsifals. I used the Shunyata Gemini with my dynaudio Special 25's and C1's but found since investing in the Parsifals I wanted something with more detail, the shunyata's can be a little "warm". there is a slight difference but the heimdalls do open up the upper frequency's a little, are not bright, and seem a little more musical and full in both the upper and lower extremes. Both the shunyata and heimdall are super in the mids. All things being equal I prefer the heimdall with my verity's, the gemini with my dynaudio's.
Try a pair of Coincident TRS Extreme. 8 gauge. Made a huge improvement. Tighter bass and 3D soundstage. With in your price range
I've succesfully paired Dyns with Auditorium 23 speaker cables from Germany. Its quite a good match.