Lose the thumbs. Lose the rules.

"... if one follows this rule, he or she can confidently build skill in a positive way, without forming any bad habits."

This is liable to revert to one of the hoariest old topics, about methods, regimes, and attitudes to aims and achievements in general, but I would suggest that one (mostly British) view would be as follows :-

If avoidance of bad habits is your aim, then don't bother with the slavish application of arbitrary rules. That is a *very* bad habit.

On the other hand, if you wish to achieve some goal, a good strategy would be start trying, now, instead of using your time planning and scheming.

If you insist on setting out a method before you begin, you could at least spend a little time considering why on Earth a method such as you may propose (practising only one more than you can juggle) is going to be more effective than, for instance, an equal amount of time spent in entirely disorganised practise, doing whatever you feel. I know that carefully structured regimes often look really good and useful on paper, but do you have any evidence that such plans *are* in fact any better than some other method, however strict or structured it may be?

I'm not a numbers juggler, but if I was, I would want to learn to *enjoy* numbers juggling, not just running the damn things. Consider your goals - do you wish to juggle numbers at any cost? Or are you hoping to take some pleasure from your efforts into the bargain?

Above, good luck, and *please* enjoy the process.

(Pardon me if I seem a little curmudgeonly today, but all of the above is meant quite sincerely. I hope it helps somebody, somewhere.)