We've got a 7:20pm reservation at CG and the fireworks are at 8pm. We'll plan to get there at 7pm in case some tables are available early. Hopefully there won't be a long wait.
The only other time available was at 5pm. We didn't want to be obnoxious and park at a table for 3+ hours. IMO that would be much more inconsiderate than booking additional ADRs at multiple restaurants for the same meal. At least if you overbook and don't show up for an ADR, they can give your table away to another guest. But hogging a table for hours and drinking coffee while other people are patiently waiting to eat is annoyingly rude.