Lotus position right knee floating?
The position is something that your should choose to help in meditation, i.e., being able to be in the position for a long time without issue. Dwelling too much on what is the right posture is leaving the main task at hand and concentrating on auxiliary tasks. The danger in this is that this can lead to trying rights or ritual like practices which has been case in some schools of Buddhism and in India.

Also any your posture can be taken into practice of the 4 frames of mindfulness. The posture it self (sense through the outline of sensations) and the pain that results from being in it for a long time.