Did the OP mention recording unknown sources at random in the field? Even if this was the case if you're struggling with 24 bits then you're recording too hot or your equipment is too noisy. In this particular case 32 bits will be advantageous - there are always exception cases but as long as your pre and mic are quiet then 24 bits will give you an acceptable recording from a tiny whisper to Concorde taking off at the same gain levels. This will cover 99.9% of "normal" recording requirements - you're clearly doing something more left-field - fine - but I don't think it matters to the average recording artist.