If you're never going to leave it in the water more than a week- why not just leave the hull alone? Just hose it down with freshwater each time you load it on the trailer, and I think you'll be fine.
I decided to go this route with my '74 C22. There doesn't seem to be any good reason to do any kind of painting or bottom coating on a trailer sailor. Blistering is a non-issue- it rarely happens on C22s even if they're permanently moored and neglected, and never on a boat that is stored out of the water most of the time. Bottom growth is also a non issue since you're not planning to keep it in the water long enough for anything to grow. I think any work done on the bottom would be a waste of time and money without benefit.