What interconnects and power cable are you using. Based on internal pics of your equipment, the Nait5 might be a higher-resolution device, where the Creek might be slower/warmer. I cannot state that for sure since I haven’t heard either equipment, but it’s an assumption based on the circuit designs (Nait5 appears to use a lot of SMD type bipolar devices, which are faster and quicker with higher resolution).
As far as NACA5 is concerned, it appears to be stranded copper speaker wire. The strands are large gauge and the speaker wire is very stiff. Not sure if you will be able to get warmer/softer, but fine stranded 12awg (like monster) may help.
As far as interconnect, the Wire World Eclipse 7 will probably do what you want (unless you already have something similar). The Eclipse is somewhat on the soft side, but it has all the bass/midbass impact and all the details are there. System synergy can be a factor here as well.
But sfall is probably right as he has direct experience with all related equipment.