Wonderful! I'm always delighted when anyone finds that their equipment (whatever it might be) meets their needs. We so often hear tales of woe and intrigue that one might wonder if satisfaction is even possible. Good show!
That being said, and with apologies for sounding like a nit-picker, but I wonder where OP finds highway slopes graded in degrees? I've never seen them thus described. Certainly the markers I HAVE seen along the highways and interstates have always spelled out the slope in percent, as feet of rise/fall per 100 feet of horizontal run. And the difference between a 6% slope as thus defined and a 6 degree slope is significant. My calculator tells me that a 6 degree slope is a 10.5% slope (and assuming this geezer remembers his trigonometry correctly, some 53 years after taking it), which would make the OP's experience really, really great.
So, my question to the OP is where, exactly, it was that he found that grade described as a 6 degree slope?