Swing Joints
How many elbos in a proper swing joint and is the length of the nipples important
three
length depends on pipe diameter.
Cost is what you spend , value is what you get.
swing joints - no easy answer
No easy answer, 3 elbow swing joint is considered the "cats pajamas" for entering a building from a riser from the ground, if it is piped correctly. I have seen more, but less won't do, unless it is a sizzor joint, which is for a different application and then you could still use 4 or more there, depending. If it were easy, they wouldn't have paid me $millions$ over the years to do it right...
Length of nipples depends on pipe size, but typically 4 to 6 inches (depending).