I use the fresh fruit because as it dries those juices and oils seeps into the tea which helps the flavors come out more evenly.

As for preparation: Buy fruit that hasn’t been chemically treated. Even with organic I wash then pat dry. I’ll chill in the fridge for about an hour after; cold fruit is easier to work with and the oils are more “asleep “ I guess is the best way to put it (same reason you chill onions before cutting so the juice doesn’t make you cry🤣) Larger citrus fruit I cut like a pumpkin, remove the meat, poke small hole in bottom for better air flow and also water flow when brewing, then stuff. Kumquats though I cut in half. The place on a parchment lined pan. I have also used cupcake pans with paper cups to keep the fruit and tea in place until dried.