I have not tried it on VHT, but on a track that is sprayed with sugar water i have found a difference with one product ....... Try marval mystery oil . I have played with everything there is and this stuff seems to last the entire run and doesn't fade off after the first two laps.
Softens them up and they are more tacky than sticky. Everything else seems good for a lap or two and fades off. The marval seems to work into the rubber better and last alot longer. I have used it for about two months and have not found anything better . Also have not seen any ill affects on the tires after using it .