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By "tines" I assume that you mean "runners".
My blower has adjustable runners on each side. That sounds excellent. (Just make them adjustable ?)
1. My blower works best when I really feed it a lot ! (Don't go slow.)
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The trouble that comes with the runners, (i call them "shoes") and i adjust them on my machine every year, is that there is also a scraping blade inside the "throat" of the blower, which will actually get up all the stuck material on the ground, you dont want the actual auger scraping the ground (you will ruin the machine and wear away the auger itself) you can try removing the scraping edge as well in an attempt to get rid of the heaviest material and have still a little clearence to keep the machine from picking up stones.
the reason it works so well when fed alot, is there is all that weight of snow on that scraping edge, thus providing down pressure so it scrapes better, which in turn puts more snow into the throat to give more pressure... a little trick you can to is to just mount one or two steel plates, old barbell weights, whatever you have, to the top/front of the machine to give more weight on the front so it scrapes better as well, its this then makes it hard to do a "wheelie" so you can turn it around swiftly, but it makes long stretches of heavy packed white cement go alot easier.
Again, what i have found out after years of taking care of a commercial storage property where people were driving in and out over the snow all the time, it was easiest to let a thin "film" of snow develop to cover the gravel, and then you just plow and maintain that surface. think of any ski mountain, the parking lots are snow, but its that "crunchy" stuff that you get decent traction on, and if more is needed, plain sand will add traction without melting this protecting layer.
-Steven