*Lots of words incoming*
I have read here and else where that for a 24g 3-5 fish would be ideal. I personally think that getting to 5 small fish is pushing it but you can compensate by doing more water changes and being vigilant with the tests. Also, why would you feel bad for only adding one clown? Depending on which species of clown you pick they can be aggressive. In which case you would only want one because they would definitely pick on each other not to mention the other fish dynamics. If you were going to do clowns stick with the Ocellaris, both black or orange versions would be nice. I would personally go for the black since EVERYONE has the orange Nemo but that is my opinion and they do run a bit more. The only reason that I can think of why you would want to add more than one clown would be to get a mated pair. However, it has been a few years since I read up on these guys and new information could be available or I'm just having a brain fart. Someone else may confirm/deny what I have said about more than one. Anyways, good luck with finding new fish, I find researching half the fun, and post pictures of the new adds.