First - 1000 watts is the max output of your amp, so unless you are using it to drive speakers in a very large hall I doubt very much that you are coming anywhere close to using 1000 watts of power
Second, Classe amps are a high current Solid State design and as such, speaker cables having a high capacitance can drive amps of this design to a point of oscilation which can seriously damage the amp i.e. damage the internal circuitry
High end Cardas cables have a very high capacitance, so this is one brand of cable I would steer well away from - they are great for tube amps though.
An aquaintance had this same problem with his Ayre amp and later his Gryphon amp and TOTL Cardas speaker cables - very costly - switching to lower capacitance cables resolved the issue
I am of the opinion that the cables you have are perfectly adequate for your setup.
If its the quality of sound you are concerned with, try Hijiri cables for a more refined presentation
As a comparison - a 1700 watt hairdrier normally has a significantly smaller power lead, so the efffective gauge of the Nodost cables is more than capable of handling the power at play here.
Regards - Steve