In looking again at your system I am not so certain that your amp has enough power for your speakers. I couldnt find specs on your speakers, but they look they would favor current.
To compare my experience with steaksters, I found power conditioning to be a detriment in some areas and helpful in others. One step forward one back scenario. But I have good power and live in a rural area. Of all cables I found digital power cords and I/Cs the most impactful. Then speaker cables, followed by power cords. But in none of these situations did I find that cables werent good investments and bordered on component level status.
If you are looking for empirical data I think you should choose a new hobby. So instead of deciding before listening and confirming your personal bias, perhaps try rsstehno's advice and try multiple cables at once.
Be careful with cartridge compliance with your Rega arm.
Enjoy!

