Boarderguy
Chief Narctopus Wrangler
And doubles/SM are the only form of acceptable air redundancy. Helium is necessary for below 100 and you must stop every 3m during your ascent... other's gear has zero affect on meWe are talking about a component that is prone to failure, not a brand, a color, or a regulator configuration.
Unless there is a valid reason, e.g., medical tooth/jaw condition, there is no need for a swivel. And yes, you're absolutely right, you should dive with people who match your risk profile. Overhead and tech taught me to be very selective.