Spenc,
That's a tough one to answer. True the air under the sled affects traction, but on the otherhand more studs means more horsepower being used to pull those studs out of the ice.
My personal preference would be just enough traction to keep the track from spinning on the big end. This is easy enough to see. When you make a run down a virgin piece of ice look out near the end for the stud marks in the ice. They'll be hard to see but their there. If you just see pick mark you're not spinning the track, if you see some scratch marks more than likely the track is loosing traction with the ice surface.
One other factor to consider is the surface you're running on too. If the ice is white it isn't very good for traction. You need to find the black hard ice to make the most of this test. And as always sharpen, sharpen and sharpen again the studs.
adrenalator8,
You might be at the maximium MPH for the horsepower you have. You need to consider the frontal area, or hole that your sled is making in the wind at speed. That takes horsepower to make that hole and factoring that in there may not be any left to accelerate the sled, no matter how far you run.
But it can't hurt to try. Nice thing about changes is only 3 things will happen. You'll go Faster, Slower or Stay the same. I think I'd try to stick alittle closer to you current ratio. Going to 1:50 to 1 is about a 15mph change and I don't thnk you'll see the benifit of the extra gear. Try 1 tooth smaller on the bottom or 1 tooth bigger on the top.