Jeff:

The Wolf installation instructions show a 7 1/2" opening height on page 87. That's what I'd go with.

Here is a link that might be useful: Wolf

Thanks, Trebruchet-My Wolf is an older model with open burners, and the dimension listed as 7-1/2" is actually 9-1/2 on my cooktop. It's a bit of a beast, but I really, really like it.
I went by the local high-end appliance place today and looked at their installed ranges. Some were flush, but others were raised above the countertop. I think I'm going to go with a 1" step. At 6'5", I'll hunch less, and I figure I can always incorporate some sort of stone trivets to the sides to protect the butcher block.

I have a bluestar rangetop and the top is about 7/8" above the surface of the counter. I was curious about how it would look, but now that its installed, it looks right. Flush with the counter would not have looked right.

The bluestar installation manual says 11/16 minimum over the counter top.

Thanks, Sonny! This Wolf is pretty chunky, and I think that having it flush would look funny on the lower part.