I have never thought my skis were too slippery. I've never wished for a slower ski. I have taken measures to slow down when too much speed would be detrimental to finishing.
Points have been made in this thread about setting expectation levels with younger racers. Parent's should be gauging their child's interest and ability. Too often the racers are on the hill because their parents put them their, but the racer would rather be elsewhere. Don't force it. Nurture it.
It has also been suggested that learning tuning skills at a younger age will help a racer develop. Racing isn't just about winning. For kids it is an opportunity to take responsibility, learn and actually reap the rewards of the efforts. It is a great life lesson. Racers and former racers have initiative, drive, goals and the knowledge that hard work and discipline pays off. Racers and former racers are great employees and leaders.
OP, don't worry so much about the number of coats of wax, etc., but use the time you spend on your kid's skis to engage your little racers in taking responsibility for equipment, the benefits of preparation and finding out what turns them on. Not necessarilly overtly, but so they understand the entire process of racing isn't just training and racing gates. And you understand what it is that they want to achieve.
Development is a continuous process. Success is measured in things besides ribbons, pins and trophies.