Am I reading this right? I looked for WOB numbers for OC regs and came up with this:
Divernet | Group tests | 15 Regulators on test
50m depth with 63 l/min ANSTI test.
The best reg was the Atomic Z2 at 0.72J/l. Most of the regs were below 2J/l
Against this, only the Boris has a WOB below 2J/l.
I suppose it makes sense since you're breathing through 2.5kg of kitty litter. Makes it pretty clear that you should be far more liberal with the helium that you would be with OC.