The latest thinking is to keep has much cash in your pocket and not pay for audio illusions that amount to delusions...Yes, by those whose systems are not resolving enough to show the audible differences in cable.....but not for the many of us A'gon members here where such power cables can make a very significant difference.
I have found the higher gauge cords designed for power amps and conditioners are also a better match for tube line and phono stages as well as tube DACs that have tube power supplies. So my suspicion is that the same would apply to your amps even though they have low power-output ratings.
Not many companies actually make power cables for both high and low power consumption products. But one which does, Dream State, I have much experience with. When I tried each type of cable in my system, the lower-rated cables worked best for components like the CD player and electrostatic speakers, and the higher-power rated cables worked best everywhere else. The only way to know for sure is to try both types of cables on your amps. Good luck on this.