How many minutes is the estimated duration for "Qayd Rumh" (the length of a spear) for Wudu (ablution) for Duha (forenoon) prayer in Egypt after sunrise, and how do ordinary Muslims in Egypt estimate the end time of Duha?

The time for ablution (wudu') for the Duha prayer for someone with an excuse (ma'dhur) begins with the entry of its time, which is when the sun has risen to the height of a spear. This time is estimated to be about a quarter of an hour or slightly more after sunrise. Ibn Uthaymeen said that a quarter of an hour after sunrise, the time of prohibition ends. Ibn Baz affirmed that the time for Duha prayer begins after the sun has risen to the height of a spear, which is approximately a quarter of an hour after its rising. As for the time when the sun is at its zenith in the middle of the sky, it is a slight time of prohibition before Dhuhr that is not long enough to pray two rak'ahs.