The Original Posting Person gets the service here. Helpful to newbies. The goal in this thread is to speak to he Original Posting Person, who has the problem.
If you think you want to move the pipes around, changing the place where the Wye connects two drain branches or arms, you Must know the total distance of the proposed NEW pipes, and their fall (drop, slope). This is a helpful reminder. I mentioned the 2" pipe in my previous pipe because this is the one that is proposed to be longer than before.
Some of the pieces of advice you received in earlier posts Do Not take this into account. To avoid causing a big problem, post an accurate drawing, or post again about distances.
If another reader wants to know more, stay tuned and come back when this thread grows longer, or go read other threads about total developed length of DWV pipes.
Hope this helps. This post reiterates my previous post. Hope you enjoyed the reminder.