The best wattage for freebase e-liquid depends on the ohm coil you are using, the type of vape device you are using, and your personal preferences. If you are using a coil with an ohm rating of 0.6 or lower, you will need to use a wattage of at least 40 watts to produce a good amount of vapor. If you are using a coil with an ohm rating of 0.8 or higher, you can use a lower wattage, such as 20-30 watts. If you are using a sub-ohm tank, you will need to use a wattage of at least 60 watts to produce a good amount of vapor. Sub-ohm tanks are designed to produce large amounts of vapor, and they require a higher wattage to do so.