We've been on the line, awaiting the vehicle next to us before it's our turn -- when said next-door neighbor wouldn't fire. The starters were kind to us, especially when we explained that we needed XX-seconds between starting the engine and leaving the line for our run, said time being necessary for certain clock functions in the bike to complete their start-up cycle. And we also would have to button/zip/velcro those last minute things like the top of the zipper on the leathers and the neck strap on the helmet -- things that we don't do until, for instance, the vehicle next to us leaves (so we don't suffer excessively from the heat).
Both Nancy and I wear two-piece leathers, and we usually put on the pants way back -- maybe a half-dozen vehicles behind the line, so it's 12 that have to run before it's our turn. Then, with maybe 5 or 6 more before us - we'll don the jacket and start the final dressing/getting ready. By the time we're one vehicle back from the line we've become pretty much fully-dressed, and have removed the rear stand from the bike (we don't do that 'til the latest possible moment so the rider doesn't have to use some of his heat-sapped energy to hold the thing upright). So -- when it's our turn to be in front of the line, the only stuff left to do is what I mentioned above -- Zip, tuck, fasten, start the engine, wait the timers, and then wait for Jim or Wes or bob or whomever to give us the "go" sign.
And the crew that's helping us makes sure we're hydrated, and we wear those water-soaked neckbands 'til the last possible moment, too.