I understand what your saying and have traveled that road a bit myself in my 50+ years of being a audio enthusiast. For myself the final answer was to build the most accurate, cleanest system I could afford. Your path leads to a sonic dead end, once you've populated your system with turntables, tubes, high distortion solid state pieces and alike, there's no way out except to replace all that gear with cleaner stuff. If you build your kit around the best measuring, most accurate pieces you can, it is dead simple to add in FR variations, harmonic distortion devices, and all the rest to tune the rig to your taste. Some day you might be interested in hearing what the artist, engineer, producer, etc; wanted you to hear when he created his piece of art.Once I embraced the concept that if I was going to set up a system for me, I was going to get what sounded good to me, and no other criteria (almost). That lead to me using 1980s vintage Conrad Johnson power amps. Not the most accurate by any means. The design has been said to color the sound warmer and softer. Perhaps, but I use it 90% of the time coupled with the Tate, which tends to sound rather brittle, so does it cancel out? Long story short, get what you enjoy. Screw the testers and the snobs.
You haven't stated the actual distance to your speakers but still I would only comment that 16 gauge wire is on the thin side for what I would chose. It's possible to introduce your speakers impedance, amplifier output impedance and damping factor, and the LCR per foot of the cable of your choice and determine the minimal size needed so as not to introduce any audible changes to the signal.. But that's a big PITA and just using a good OFC twin lead of 12g for runs up to 25 ft and 10g for up to 50 ft will put you in a comfort zone where there's no worry of signal loss/change. Wire of this type can be purchased at a very low cost from suppliers like BlueJeanCable custom terminated, or Sky High Car Audio cable which is what I have in my rig now. Don't let the "Car Audio" branding scare you, it just has insulation designed to withstand temperature and humidity variations that aren't usually seen inside the home. Very nice flexible stuff in a large variety of gauges, colors, and lengths to suite your needs at a reasonable cost.My rear speakers, since the cable has a lot further to go, are 16 gauge lamp cord. The fronts are a little 'fancier' since they are shorter. But I don't hear any difference.
What do they sound like, the source, what else. LOL