It dosen't matter a whole lot what your inerts are (He or N2), except in small subtle ways - the He offgases a bit sooner (deeper). It is all just inerts.
The trick is to achieve quality decompression, right from the end of the bottom time - and there are many factors that you have to get right to achieve this (too many to explain and get the right emphasis here).
In very very brief (AND PLEASE DO NOT FOLLOW THIS ALONE):
Hydration (previous 24 hours),
Circulation (moving most of the deco) and
Open the oxygen window (increase ppO2 if you feel OK and are not using large muscle groups - watch your buoyancy).
Seeing as this is a tech forum, I can say this here (cos I know that I will not be shot down in flames, don't I!).....I know a guy who cut 103 minutes of deco off his Vision software after a 42 minute dive to 105m last Monday, without any worries of becoming bent. Total dive time was 3 hours and 50 minutes. DIL was unchanged during the dive and was 6/70. The set point was changed from 1.3 (during the bottom time) to 1.5 just after the ascent began. CNS clock was almost 200% at the end of the dive and OTU clock was about 150% (deep dive the previous day).
By the way, in case you are wondering, the time cut off the deco was not that based on a 1.3 set point whilst leaving the bottom - it was the time remaining allowing for the higher ppO2 during the dive.
Th diver left the water when the loop volume kept collapsing and the ADV was trying to cut in, whilst running on pure O2. Hence, no more inerts being offgassed.
If you want to know more, you can come to one of the talks that Stephen is hosting - probably in January or February.
Cheers,
Stewie
