Hi,
I believe that you should be fine with it.
Of course you’ll have to paid attention where to locate each (type) coral.
Next to that, you can always add more Kessils in the future if the corals starts to get too big.
I suggest you to see BRS videos explaining how to space the Kessils in order to have the best light distribution.
Let me know if you can find the videos.
Cheers