Piebald is recessive which means that you need both the parents to carry the gene to produce a visual. Piebald can either be low white or high white. This depends on the parents but is polymorphic, which means that high white parents tend to give high white babies but can also give low white babies. The content of the white can be influenced by adding other genes. the white is usually concentrated in the last 50% of the snake. Genes that increase the white in a pied are spider, spotnose, lesser/butter and cinnamon/black pastel. Spider can be very extreme is this regard. A spider piebald is often referred to as spied and only has some pattern left on the head (or no pattern at all). The lesser piebald can sometimes have smaller eyes then normal. Enchi piebalds tend to increase the pattern and lower the white in piebalds. Most other genes usually do not interfere with the white content. Yellow belly and orange dream drastically increase the orange in piebalds. 
We got a little late into the piebald project but tend to increase our piebald stuff. Right now we have:
0.3 Piebald
0.1 Enchi Piebald
The white of piebald does not change into adulthood but the pattern part does turn brown while ageing.