10x, 20x, 40x, 50000x, they aren't standardized strengths so you can't figure out how strong it is without trying it. That being said, 20x is usually pretty potent. You can certainly use it, but you will need to adjust your dose accordingly. Start with a very tiny amount for your first time and then increase the dose on subsequent trips until you find a dose you are comfortable with. Use a milligram scale.
Salvia is an extremely powerful drug, so give it the respect it demands.