SCINFERNL
+1y
Dearched leaf springs are fine, and not inherently dangerous if they're dearched by a reputable shop. Never run a single leaf with an adjustable suspension though, it will break eventually. Instead, de-arch the full pack if possible and run that until you can afford a multi-link suspension setup.
Can't comment about scuba tanks... super high pressure for air ride scares the shit outta me and always has. No one's life is worth having an adjustable suspension.