On a two lane highway, I will never vary my speed even up the steepest hills, except to let my speed drift up going down a hill. On a four lane highway, I don't see the issue. If you don't like the speed(s) that I'm going, just pass me. Some people do it wrong though. They bomb up the hills then ride the brakes going downhill. They probably complain about crappy fuel economy too.
X-Traction, it was my 2012 Mazda 3 Skyactiv. That was going 5 above the limit constantly on the two lane sections (except down hills) and the speed limit on four lane sections including 110 on the Coq with a drift down to 10 under and drift up to whatever I felt was safe. Even coasting in 4th gear in my 6 speed manual, the car picks up good speed down the snow shed.
I have to note that I haven't owned a single car that's been able to do the speed limit up the snow shed. I usually do 80 up that hill, going up the centre lane. I'm in 2nd gear at over 5,500 RPM @ 85km/h, I try to upshifting to 3rd in which during that shift I lose a few km/h, then I'm down at 80km/h at 3,500 RPM and losing more speed because there's no oomph, so I have to downshift to 2nd again where I lose even more speed to 75 and it takes me 30 seconds to get back up to 85. Lol. That was my Mazda 5. I think my Mazda 3 is better.
But anyway I blow past semis which don't seem to be going faster than 20km/h up the right lane, and then Grand Cherokees and F150s blow past me doing the speed limit. Once or twice I've encountered a semi in the middle lane going 20 trying to overtake another semi that can only go 15. That's forcing me to get into the left lane to overtake these two semis and it's not a fun situation.
Maybe they should build a fourth lane up the snow shed and prohibit semis from the left two lanes.