Sounds good- it's also possible that this will resolve itself completely within a couple days. I would just test regularly (ammonia) to monitor the progress. The prime will help to neutralize the ammonia, but it will still show up on tests if it hasn't been processed to nitrite yet. Just make sure to take things nice and slow and you should be fine.
That being said, I don't want to muddy this thread too much, but long term I actually think you're going to need a larger tank. That many clownfish and that type of nem is likely to spell diaster in a year or two. It seems a lot of people are doing harem tanks and they can be one of the easier tanks to maintain, but only if you have enough space to mitigate agression (and other details such as introducing all the clowns in at once, preferrably from the same clutch, etc.). I would deal with this issue first, but ultimately I would put serious thought into upgrading your tank or selling off some of those clowns. They'll get along for the first few months likely, but I can't tell you how many <90 gallon tanks I've seen start with 10 clowns and eventually dwindle to 2 clowns within 24 months....
