> with the standard vigreux at 30cm you get's desent result's.
A 30cm vigreux is way too long for a 14/20 distillation!!! That's a great way to reflux your chemicals without actually distilling it.
> A packet one only have to bee 10-15cm long.
When you want to distill only a few grams then a packed column is out of the question, unless you don't care for the yield. In case you do, get a spinning band column or something similar.