WHAT? Uh.. maybe you should look into like the other 10 or 15 smoking blends that incorporate JWH-018 and JWH-073 into their smoking blends.. as both are very potent, and Spice Gold is not the strongest blend that Spice makes.
As to salvia lasting 5-10 minutes.. that is body chemistry. Everytime I get a huge rip of salvia I am facing approximately and hour long trip, 30 minutes at the minimum. Salvia is reverse tolerant, the more you smoke, the lower your tolerance gets.