It's a good "rule of thumb" to stick to higher resistance coils and lower device power, however the release of benzene is related to temperature, not specifically power or coil resistance, soooo ... take it easy on the power, and settle for the bare minimum you require to get your fix, alternatively ... use freebase juices. I have vaped Nic Salts, (and Freebase for that matter), using SMOK RPM and Nord 0.4 and 0.6 Ohm mesh coils at 5 to 7 watts, with zero benzene conversion, (confirmed with a gas spectrometer after having this fear driven into me by other vapers in my "early days").@JuddMan Nic salts should be vaped with a coil of 0.8 or higher. Never with a coil less than 0.8. Obviously the salesperson didn't tell you this.
There's a plethora of accurate research information freely available on the subject

Benzene formation in electronic cigarettes
The heating of the fluids used in electronic cigarettes (“e-cigarettes”) used to create “vaping” aerosols is capable of causing a wide range of degradation reaction products. We investigated formation of benzene (an important ...
