What is the permissible extent for spacing between the feet in prayer to fill gaps, and are the rows straightened by looking to the right or to the left?

Muslims must straighten the rows and close the gaps, with shoulder aligned with shoulder and foot with foot. The Prophet, peace and blessings be upon him, commanded the straightening of rows, the alignment of shoulders, the closing of gaps, the softening of hands for brothers, and not leaving spaces for Satan. He who joins a row, Allah joins him; and he who cuts off a row, Allah cuts him off. The Imam should stand in the middle of the row, and the rows should start behind him, then expand to the right and left. The alignment should be between the feet and shoulders. One should not exaggerate in spreading the feet apart, or excessively pursuing heel-to-heel alignment, as this causes the widening of gaps between those in the row and distracts the worshippers.