How does your full spectrum compare with the far infrared saunas available on the market? And is the heat in this sauna from ceramic or carbon heaters?

The full spectrum heaters are more beneficial as they offer Full, Medium and Near-infrared. You will see many companies charging £200, £400 or £500 to upgrade from Far heaters to Full Spectrum. A quick search on Google would confirm this

The Vidalux Full Spectrum range uses ‘Complete Heat Technology’ with FAR carbon heaters together with quartz embedded Full-spectrum heaters