I'm getting conflicting advice (name of the game):
1) Don't go to the Structural Engineer (for spec for suspended slab and its support) until DA is approved. (Otherwise, if DA is knocked back, it will cost more in SE fees).
2) Don't put the DA in until you have the full details from the Structural Engineer (otherwise you might get approval for something that doesn't physically work, and have to resubmit DA)
Both sound very wise. What's your best advice - chicken or egg?!