Yes, you have to be a member of the USCA and get yourself a score book and membership number.
If you are going to find a different handler to show Berlin, you can ask local clubs before hand... sometimes you can ask people AT the show itself but IMO that's risky and you may not be able to find someone. You are in Illinois, why don't you ask the amazing Carlos Huerta to show him?
I didn't practice gating.. I plan on practicing with my female for when my husband shows her. I regret not practicing.. haha. Hunter just tried to run full out at first, and only started gating towards the end when he was hot and tired of running around in the sun.
The SV shows aren't like AKC/CKC... I would bathe a couple days before not the day before. A super fluffy coat hides conformation, especially with a long haired dog... so bathe a couple days before or a week before, give him a good brush before you go out and that should be sufficient.
Do to your local club trials and watch! Often before a trial the club will host a practice day for people to come out and get their dogs in the ring. I personally am not a fan of showing, so my husband is going to show our female and breed survey Hunter for me. He wouldn't agree to show him in UKC for me, so I am stuck doing that in the next few months...
It will be a great experience for you!