The ice quotient is variable and dynamic on both Shasta and Whitney, varying with temperature, cloud cover, time of day, and other considerations.
That said, the Whitney chute is more east facing (Shasta's avy gulch is west facing), so it goes into shade earlier and can ice up faster. However, in the morning, snow conditions can fall apart earlier because it gets that strong morning sun. Last year when I climbed the chute with Richard P's encouragement/coaching, the conditions deteriorated so fast that there was almost nothing left to grip by 9 am.
I do think the top of the Whitney chute is a tad steeper than avy gulch at its steepest. The incline on the chute starts milder but increases as you climb.
