It’s been a bit since I had a VF, but then Marcel recommended Nickel Low-Riders. I am sure he would be happy to help should you call or email. Or, post a photo of the bridge and tuner ends of the strings and we can try to provide additional info.
Photos of the bridge, ball ends, tuners end... I think the photos will tell a lot more about what the strings aren't than what they are, but any info will be appreciated.