I have all ARC stuff. I had high end single ended interconnects when I got my ARC amps. Audio Research recommends using balanced (preamps and amps are internally of balanced design). So I got an identical balanced interconnect and tried it. I could not tell the difference. I did not carefully listen for weeks… so there was probably a small difference… that I would have heard over time. I still swapped them all for balanced. Getting the absolute most out of a system is the sum of small differences… so some of us never let anything go at less than perfect.
So, applying this to your situation. The sonic difference in using converted interconnects is likely to be very small.
The fact that you own three preamps and are conserved with cable costs suggests you like experiencing different sound types as opposed to achieving the ultimate sound quality you can. So, I would go ahead. You are going to get the Audio Research sound from these components. Then if you get hooked on the sound you invest in balanced to get the utmost out of them.