I'm not a pilot but I came across your post searching for some similar info so here's my input:
I'm a direct employee. My husband and I successfully non-revved from VCE to ATL yesterday, June 25. I had been watching the loads for a few days. We listed as S2s but all nonrevs even down to S4s have made it every day for the last 4 days. My husband and I had to split onboard though, as there was only 1 Delta One seat left.
No payload optimization on my flight or for the last 4 days, as far as I can tell.
We arrived to VCE at 8:35ish for the 11 AM flight. We waited about 15 mins in the line to check in, another 15 mins in security. Once through we had about an hour to waste time in the lounge before heading to the gate one hour before flight time. I would say arriving to VCE 2 hours early is probably enough but I also don't know what the lines might have looked like had we come later.
Instructions while listing say that nonrevs must wait at the counter for their assignment and then, if cleared, will be allowed to proceed on through security and to the flight. Not true. When we checked in, we received the standard "seat request" boarding pass and went on through security.
If we hadn't made the ATL, we planned to swap to JFK. Can't offer any insight on that or the crew bus.
Hope that helps.