A 10 gallon isn't really big enough for a grown clown. My clown is 2 years old and 3 inches long so I wouldn't put it by itself in anything less than a 25 gallon tank and he is one of 4 fish in my 55.
I have a bubble tip that is nearly 7 inches across when fully opened and it probably is about 6 months old. It is a clone so I know it will do well in my tank. My clown decided it would rather host some sand instead of it the anemone, It is about 9 months old now and growing fast.
If possible upgrade to a larger tank and wait a year at least before getting an anemone. Even clones need perfect conditions.
This was 2 days after I got it. I have had mine for a month and it has doubled in size at least. Make sure you get a tank raised clone and you will have a better chance at keeping it alive. There is a lot of work when it comes to anemones and keeping them happy and healthy.