Thanks Osiris, but if you sail with Silversea you will not need to book a private tour. The tour the ships provides could not be any better.
They provide you with drivers, armed guards (that is not obvious, but they are there) and the world's best guides.
The ship provided tour is overnight and includes a stay in Luxor based hotel right on the Nile. The dinner on the river under the stars is a night you will never forget. You will feel like you are back in ancient Egypt.
It is a fantastic experience.