Well, it could have been a tad bigger but not much... Lee and kirby's Hulk was 6'10"-7' max. The Hulk bust proportion of the head are still bigger than Spidey, But I agree that its slightly not big enough.
Thanks Shai. To be more specific ...
In character, the Hulks head really never grows much, in proportion to the rest of the body. Or does it just change shape?
If it does not grow much, then maybe SS got the scale right at least. I look at the PF Hulk, and the head definitely is smaller in prop to the rest of the body, at least that's how I remember the Hulk.