No, they're not as good. I can't speak for rusk as I've never tried it but back when I was doing my level two I tried xp100. Its cheap for a reason, stinks of cat wee and just doesnt perform well. Wella is brilliant and consistent I'd stick with that.
Wella Koleston is really good for reds but I'm biased[emoji12]
However 55/66 is violet, not red, and very dark. I'd recommend 77/46 and 8/45 equal parts with 9% and leave on for the full 60 mins so you don't end up with root glow.
Is her hair virgin? If you can try to upload a picture of her...
Its not really a reverse root smudge if her hair is already a 9 its just a root smudge.
I would do it on wet hair as you'll get a much nicer blend. What brand do you use and what were you thinking of as a colour choice?
They have a 7/97! 7 and 8/71 are gorgeous for lowlights and root stretches, as are the /97s. 8/81 will probably be extremely cool on a level 9, silver on a 10. 9/97 would be a nice toner on a level 9 but yes it won't add a good shadow, you could mix it with 7/97 to get an 8.