What was six Amos wide?
Rashi: The thickness of the wall of the Heichal, between the Heichal and Ulam [from east to west].
Radak, Vilna Gaon: The Eilim of the gate of the Heichal. Radak - They were like domes above; each was six Amos wide.
What is the meaning of "Rochav ha'Ohel"?
Rashi #1: The width of the Ulam. [The six Amos were] along the width of Ulam and the length of the Heichal.
Rashi #2: The width of the Ohel of the opening.
Radak: The width of the domes. The dome is called Ohel. Yonason translates 'the width of Mashkena 1 .'
Vilna Gaon: The Eilim were aligned with the thickness of the walls of the Heichal. There were six Amos from east to west. They were as wide as the thickness of the wall, i.e. also this was six Amos.
Malbim #1: [The wall of the Heichal is called Ohel, for inside from the Agaf (where the door rests when it is closed) is considered inside. Outside the Agaf is considered outside (Pesachim 7:12).
Malbim #2: The Heichal had double Pesachim 2 . We can say that between the openings was like a Reshus unto itself, and its Kedushah was intermediate between that of the Heichal and that of the Ulam ? therefore it is called Ohel.
