According to Nordost, there is a big difference between the entry level Baldur and the next up level, Heimdall, which is the first level to use the Monofilament (?) technology of the Valhalla. So, they recommend to start with the Heimdall. I have the Heimdall speaker cables and they are great.
I also have the Frey interconnects which are great also, and IMO, a bit better than the highly-regarded SPM.