i believe the "polichinelle secret" to playing an even fast scale is finger articulation combined with arm drag. so: practice in slow tempo over-articulating (lift each finger as high as you can), practice in fast tempo focusing also on the arm (and esp the elbow) being constantly ahead of the hand on direction. also, practicing in rhythmic formulas can help (double dotted 8th + 32nd, and 32nd + 8th..). and focus not only on rhythmic eveness, but also on sound (dynamic) eveness.
as for particular mozart scales - maybe eveness is not the biggest problem. imho (and for me, at least), the biggest problem is obtaining that crystal-clear sound, getting that scale to sound like a perfect pearl string...
best luck