32 & 64 bit floating is fine for the internal processing of audio but there are no hardware devices able to play better than 24 bit.
So no matter what you do if your medium is going to be CD you need to dither down to 16 bit in your final processing and if your intended medium is DVD then you can stay at 24 bit.
You can export a file at 32 bit float but it is only any good for import into another bit of software for further processing. At some time it's going to hit hardware and will have to be either 16 or 24 bit.