I know this wasn’t directed at me, but I’ll give you my opinion if you don’t mind.
For us, the main appeal of the dessert party is the reserved fireworks viewing. We’ll eat a dessert or two, if that, but otherwise that’s not our motivation. For the plaza version, our preference is to arrive more like 8:20-8:30ish (assuming a 9PM HEA). I like to be out to the garden area by 8:40-45ish. I find anything more is overkill and we just waste time sitting around.
I concede this strategy might not make sense for some folks, but it works for us.
My answer would also be a little different if OUAT is before HEA, as I’d probably bump up that time a bit so we could watch OUAT from the garden.
Hope that makes sense. Happy to elaborate if needed!