I have the Manfrotto 500AH head. And it's not nearly enough. In my opinion, the bag is clearly designed so that the 055 tripod only fits without the head. Then there is still some space, but not enough for a complete video head. I simply leave the padded lid open at the top and put a Velcro strap around it. It is true that the bag for the tripod alone is generously large.

The pocket is very generous and if you can flatten the video head lever! It should actually fit.
Important, 70 cm in height!