No. I suppose if your tire is already full of sealant CO2 cartridges would be better. Just make sure to get the big ones.
In my experience the small ones are powerful enough. After filling the tyre, and the pressure is established, I use a gauge to drop it to the desired pressure.
I envisage riding these events with 2 x tubeless full of sealant and maybe the inserts that @OreoCookie pointed out. Then maybe two spare tubeless tyres incase the tyres rip, and then a handful of tubes for anything after that. Plus a load of cartridges and the gauge...
Definitely sounding more and more like a survival adventure ride than a race!
Andy