Good thing I asked the exact purpose as this is a special case.
Use the Turtle. Turtle is your friend.
Copy these to your MoSpline attributes
You can control the Angle and Movement to your preference.
As long as your opposite bars are parallel the setup works as it it.
If the bars converge or diverge though, n order to connect them with the turtle you'll need to deform the spline with the Spline Deformer which might be a bit difficult to work with.