Here is my thoughts and experiences with Clarkiis..
Clarkii clowns are one of the most "non-picky" clowns when it comes to what they choose as a host. In this respect, it is advisable, if you are just starting out, to keep either no anemone at all, or one of the "easier" to keep anemones. A bubble-tip anemone is a good candidate.
IMO, small clowns (less than 2") will not bother any shrimp that is at least 1.5" long. While small clowns do not necessarily mean young clowns, the Clarkii species is one of those species whereby if it is rather small, it is probably young. As an adult pair, both female and male, can reach the same size, and at times be difficult to tell which is which.
Clownfishes, like other animals, are attracted to movements in the water, which in my opinion is what triggers a feeding reaction. You DO NOT want to just "dump" the shrimp into your main tank, after the 'drip acclimation'. Why is this? Shrimp can take a long time to go down from the top of the water column to the bottom. At times they will dart/scoot away backwards, and this will trigger a reaction from larger clownfishes.
IMO, larger clownfishes can/may eat newly introduced shrimp if introduced in the above manner. I have seen it. With regret, I placed a peppermint shrimp into my tank at the top, and halfway down its descent into the tank, my female Gold Stripe Maroon comes out, bites the 1.5" shrimp with its mouth (and while unable to eat it whole), it then proceeded go into her Rose Anemone, and spit out the shrimp. The anemone then proceeded to eat the shrimp. IMO, the clownfish didn't fully kill the shrimp, but did so indirectly. And so much for an expensive meal.
The reef-safe shrimps can be kept with clownfishes. Once settled to the bottom, clownfishes don't seem to bother, and even will go for a cleaning, or two, if you choose a Cleaner shrimp. So when you get one (or two) shrimp, please drip acclimate, and then when you are ready to place it into your main display, take the shrimp with some water into a small tupperware. Close the tupperware. Use your arms and open the tupperware inside the tank water near the bottom of the tank. You should be all set.
Best,
Ilham