Najafi Q&A: Rukoo

It is mentioned in Minhaj Al-Salihin (Vol. 1, Issue 639, p. 231) regarding what is recommended during bowing (rukūʿ): "It is recommended for the worshipper to look between their feet." Additionally, in Wasa'il Al-Shia (Vol. 4, p. 942) and Jami' Ahadith Al-Shia (Vol. 5, p. 230), it is narrated that the Noble Prophet (PBUH&HF) bowed, spreading his palms on his knees, keeping his knees back so that his back was straight. His back was so level that if water or oil were poured on it, it would not spill. He extended his neck, closed his eyes, and then glorified Allah (tasbih). The question is: Should the worshipper, before reciting the tasbih, open their eyes and look between their feet, and then close their eyes during the tasbih, as mentioned in the narration? Or is it recommended to keep the eyes open and look between the feet at all times, whether during the recitation of tasbih or otherwise?

Can it be said that the praying person is in Ruku (bowing down) when the tips of the fingers reach the knees or should there be stability?