As mumzie noted, think in terms of sport-compliant patterns that may or may not get choppy in the span of the block. Much of how a given block plays has a lot to do with who you are following...a good group can make the lanes very playable, while the pray and sprayers can make your day very frustrating if you have the misfortune of following them.
I've driven to just about every event I have competed in, so I was never limited to just trying to take a four ball arsenal. Even when I flew to Raleigh, I still shipped three balls out there ahead of time and took four on the plane (back when you could take equipment as a carry-on).
Less is more...I had a lot of pin over bridge and pin over middle finger stuff that I put on the ball card last year. The practice block won't always tell you how they will play, but you can figure out what might be worth bringing out at the start of your block.
