amascuba:I'm not a fan of deep air, but I don't currently have training with helium based mixes. There are two locations that I will dive within the next few years that are deep, but only supply air for back gas and 50%-O2 for decompression. For these dives I will dive to 150-180 fsw.
Have you done any training dives at that depth? Just curious how you felt and the degree of narcosis experienced.