Michael Hookam? Don't know him. His wife wrote a PhD. thesis on the Kagyu version of the Shentong view that is currently an important presentation of that view. To me, when you say "Hookam" I immediately think of his wife. I didn't know he was publicly active.
I clicked on the link you provided, and he does have quite an impressive beard however.
There is a tradition of making a distinction between two different perspectives on the nature of emptiness: one is when emptiness is presented within a philosophical analysis of the ultimate reality of things, in which case it ought to be understood in terms of a non-affirming negative phenomena. On the other hand, when it is discussed from the point of view of experience, it should be understood more in terms of an affirming negation.