And for the ones you’re mail ordering compounded (unless you’re having them compounded locally), call them in advance, and ask them to send you a placebo sample pack with all the flavors. Most places will do it for free.
The place we used had a million (okay, maybe a few less, but still quite a few) flavors. This was particularly useful with our old cat who was very finicky about flavors. “I’ll eat prawn flavor, but not shrimp…”.