There are a number of factors that may, or may not effect how quickly you can perform a trick, whether it's a floating card or anything else.
It must be noted that you should never perform any trick that you can only perform successfully for part of the time. One of the worst things is going out to perform something, knowing that there is a fair chance that you will be caught out, and therefore expose the secret.
If an when you do get hold of the floating card then you must make sure that you can perform it repetatively without slipping up. Only then should you begin to perform it in front of others.
One last point before you ask, please don't ask for and guidance on how this, or any trick is performed (which I'm glad to say you haven't) as this is not a site for revealing secrets. Otherwise, you're welcome to look around and enjoy

Member of the Magic Circle & The 2009 British Isles Close-Up Magician of the Year
It's not really an optical illusion - it just looks like one!