I should note though, that even though the actuation force between the Topre switch, and the MX Brown switch are the same, they feel very different in terms of how "easy" they are to press. IIRC, Ripster made the distinction between "actuation force", and "work", which can differ between switches, even though the switches have the same actuation force.
That said, it seems the MX Browns are easier to press than the Topre switch (even the 45g), even though they have the same actuation force. I still prefer the Topre switch, though, because I don't like the "springiness" of MX switches. But that's clearly personal preference. Other people have written in other threads that they actually like and prefer the springiness of MX switches, so, again, personal preference.
I don't own an HHKB (I own a Realforce 87u), so I can't speak on its layout, however.