It is actually best to run two identical pairs of cables when biwiring. I have been doing that for over 30 years with great success. Before I had a second pair of output jacks on my power amp. I doubled up the spades. Just tighten the jacks well so you are getting good contact to both spades. It will be even better if you have a second pair of jacks added to your amp.
What amp. and speakers do you have?
What amp. and speakers do you have?