Based on the discussions in this forum, I get the impression that the typical way to draft trouser patterns is to have the side seams of the back and front have the same length on the pattern, while the inside leg seam of the back pattern is shorter than on the front. This seems to be the case also in the Runschau pattern that I want to use.
However, some pattern drafting systems seem to result in a pattern where the back has a longer side seam than the front, where the idea (to my knowledge) is that the extra is taken in as ease at the seat. Also, looking at instructions for ironworking trousers (e.g. http://www.cutterand...p?showtopic=435), the back seems to get more shrinking than stretching compared to the front, which would require a longer side seam in the back to start with.
If starting off with a pattern with the same side seam lengths on the front and back, I guess one way to achieve the same side seam length at the end would be to stretch the back much more at the knee than the front is stretched at the calf, so that the resulting side seam length is the same even if the back is shrunk both at the seat and calf. Is this the way it is usually done?
Is there something I am missing? What is your take on this, would you still recommend a pattern with the same side seam length, or one with a longer side seam length on the back?