As you say, you have no baseline for comparison. I would put the Oppo back in, let it run for a few days, and listen. Alternatively, put your old cord back in the system with the new player and listen for a few days first. Either of these suggestions will give you some sort of a baseline, which you totally lack at this point and are therefore unable to evaluate the VD cords really at all, since you introduced another unknown variable.
Additionally, a new VD PC will probably make a more pronounced difference plugged into the CD player than the pre-amp. I would therefore really try to make that work - the cable bending can be a challenge, but is definitely doable with a little thought. For example, my CD player is 5' off the ground and I have a Genesis PC attached(a lot bigger and heavier than yours) with no problem. I'm sure many others have gone thru similar gyrations so you are by no means alone. Obviously we feel it was worth the drain bramage. Good luck
Additionally, a new VD PC will probably make a more pronounced difference plugged into the CD player than the pre-amp. I would therefore really try to make that work - the cable bending can be a challenge, but is definitely doable with a little thought. For example, my CD player is 5' off the ground and I have a Genesis PC attached(a lot bigger and heavier than yours) with no problem. I'm sure many others have gone thru similar gyrations so you are by no means alone. Obviously we feel it was worth the drain bramage. Good luck