I have done, but not for a couple of years so I'm not sure how the last ones have gone. Where are you thinking of parking?
I don't expect all the entrances to be open really early, so I think you might have to go in through the entrance on Chantry Road. That's what I've had to do before.
What might be worth doing is to email Chapelfield themselves and ask them how it might work - as I say, I haven't done one for a while so don't want to give you mis-information. You can email them on
chapelfield.information@intu.co.uk. They also have a twitter feed that I think they post info on, but that probably won't be until nearer the time and if you want to plan, that won't help you!
The last queue up's I've done have been for iPad's and when they've opened at 6pm so I'm not sure about the best time for a morning launch...I'd kinda hope you wouldn't need to get there at 4am like some of the other locations!
Not sure how much use this post has been really, but thought I'd try and answer as best I could...