Thanks effie. All that was known to me beforehand, but I held it back to avoid prejudicing responses.
The set certainly was photographed by VT, although whether that's Viv or Chantal could only be determined if it is found in a mag that names the photographer. It has never been published on the VT website, which might support the Chantel hypothesis.
There are numerous girls on VT's site with variations of Niki or Nikki or Nicky or Nicki or Nicole or Nicola or ... etc. The two that I had thought were most likely for mystery were Niki A and Nikki A, but my model IDing skills are so bad that neither really jumped out at me.
For various reasons, I knew that the VT reference number of the mystery set must be in the high 1000s or low-mid 2000s. Both Niki A and Nikki A fit that history. Here's a little body check for comparison.
Niki A:
Nikki A:
.