OK -- now I get it. Thanks for that. I knew there had to be a good reason for it, and it all makes sense.
BTW, just as a general comment -- the only guys here who race are you and Liam (I think); all other riders on this board do not race. So we have other priorities for our gear, other than speed and shaving seconds off a lap time.
So my tire needs have more to do with good grip in corners, roots and rocks, and for climbing; low rolling resistance; low weight; versatile performance in a variety of terrain, incl. wet clay; and quick agile handling. How fast a tire is on a course, or what setup a pro racer has, doesn't matter at all. You guys have different needs than I do.
OTOH, how much the tires wear me out does matter -- I've ridden full-suspension all-mtn. bikes with big beefy tires weighing almost 1000g each, and near the end of a 3 hour XC ride I am ready for a mule to carry me and bike back to the car. Getting those hummers spinning up to speed and trying to climb was like having lead weights on the wheels. Fantastic grip in some of the gnarlier terrain where I rode them, but for everything else, forget it.
Up to now, the Slant Six has been surprisingly good for the terrain around here. Probably not the ideal tire, but the best I could find in the shops last autumn near end of season. I would have preferred a Saguaro, Ignitor or a Nobby Nic, but just could not find them in 29". I will keep the Slant Six on for at least this season, put them through a beating in some rougher terrain and see how they manage. My experience with different types of today's tires is rather limited, but I did not expect the Slant Six to perform as well as they do, given some of the so-so comments here about them. OTOH, test reviews on the web have been almost 100% positive about these, with only one luke-warm review that I could find. If I punt them in a couple of months for something else, I will let you know.
Thanks again!
Svend