An update on the situation. I've decided to stick with audio sensibility as I only need one short pair of interconnects and two power cables to complete a full loom. I can then use this as a baseline for any further upgrades.
As for speaker cables for the time being before deciding if I want to go really big in the future I got a pair of raven audio soniquil cables. Banana plug connectors. Now I can't tell if its the fact that they were replacing dollar a foot classic Belden 9497 speaker cables or that they are just that good but damn I was heartily impressed at $184 for a 6ft pair. Immediate opening up of sound and have gotten better over time now. Not sure if going big on speaker cables is as much of a top priority now lol!
Oh one additional thing I did that had a dramatic improvement was replace the 1980s withered wall receptacle with an orange outlet from home depot. It even said recommended for computer and audio applications on the package which gave me a good chuckle. $9.95 but low and behold there was a noticeable difference. Before there was a slight audible hum within 3 inches of the speaker when everything was turned. I had assumed that was just a casualty of running the all tube preamp and was fine with it as at my listening level its not an issue at all. With the orange outlet now though it is dead quiet. You have to practically dig your ear down into the speaker to hear anything. Not sure if this means lowering the noise floor or something but it sounds better to me so all good!