I do not know how many he threw with the Prophet ﷺ.
حدثنا سليمان بن حيان عن ابن جريج عن أبي الزبير
لا أدري بكم رمى النبي ﷺ
No references are available.
Its isnad is sahih, and it is found in Abu Dawud 1/457, in the book of Hajj, chapter on throwing the pebbles at Jamarat, and in Nasai 5/223, in the book of Hajj, chapter on the number of pebbles.