Hi.
Here is an old post of mine that may shed some light on the question :
In this post I used different numbering formats (letters etc), but in short you’d then have to number your files in this fashion, only rather use <$n> strings instead of letters.
And so as for your question, limit yourself to the number of digits you want to print.
Use the right strings that correspond to these specific digits (this way you may omit digits that would otherwise have been at the beginning of the number), and voilà.
If you want 1.3 to print where it would otherwise have been 2.3.1.3, it’ll work. (You may omit any digit you want, no matter where they would have logically been. Beginning, end, middle, it doesn’t matter. – Doing it this way, “manually”, you have complete control.)