Good luck to you and Bailey, I use a standing wait command with Cosmo Now, I started with a sit stay but switched once I knew he knew what was expected of him, the differance is around .3 to .5 seconds depending on the dog and how he starts,on the standing start vs sitting, and yes that .3 sec cost me a Q for a title, thats the reason I switched, with a slow dog you need to take any possible advantage that you can, if you are driving a rocketship or very Hyper dog then the sit or even a full down can be a much more stable starting position and I found it easier to do a much longer leadout from Cosmo in the sit, from the stand I rarely lead out much past the first jump if that, from the sit I used to lead out 2 to 2 & 1/2 obsticals so the Standing start is a bit more running for me not a big deal though.
With the pup I am using a full down stay right now and even then she will start creeping in anticipation.
I am sure you will be way more nervous then Bailey, I know I was, but just try to stay as cool as you can . always easier said the done. trail 1 was a bust for me, trial 2 was much better and by trial 3 I finally started to feel comfortable with it and Cosmo was an old pro.