I memorised quotes and techniques for my half yearlies, but memorised essays for my trials and HSC. I performed equally well in both, but felt more comfortable with a prepared response. I knew my texts very well, though, so I could worm my way out of sticky questions.
I recommend you practice with quotes and techniques so you're accustomed to thinking flexibly. At the end of the day, you'll be doing a bit of both, because if your essay doesn't fit, at least you will have remembered quotes, techniques, and structure. I never truly memorised 100% of the response (read and recite before bed, sleep on it, remember 95% of it in the morning) so I wasn't stuck trying to recall things verbatim.
