rosami,
I don't have any experience with Naim cables, but you could be right about the Thiels needing different speaker cables to perform their best. I'm still using Straight Wire Encore cables from the 1990's because I know they're a good match for my 2.2's. Several weeks back, I spoke to Jerry Willsie at Straight Wire about my Encore cables, and he said they were still a great match for my Thiels. In fact, he said he had just recommended a version of the Encore to Kathy Gornik (one of the original Thiel founders) for her Thiels.
In your situation, you may want to use the lending library at the Cable Company to try a few different speaker cables. Or you could try a cable maker that has a 30 or 60-day free return policy. Tom Thiel has recommended Morrow cables. Ronkent has recommended Cardas Clear Reflection with his system. Unfortunately, speaker cables can't be selected based on the performance of interconnects of the same brand since cables typically require a different design to function well with speakers.
Good luck in your search!