Yes we have had that problem. There are a few options in the database.
I attached a screen shot of how we have our insulation developments set inside of our most common liner. We also lie to the computer and tell it that the liner is 1/2" thick when it is really 1" thick. Our guys have trouble centering the liner on the fitting, so they had gaps on one side, so the boss said to lie to it so that the liner is actually squished in there on the edges.
I also went into the radius elbows and set the INSULATION PARTS option to Wraps Inside.
On the square elbows we make the throat and heel liner in 2 pieces each.
The length of the liner is still not perfect, but it is better. I think the heels may be a little long, but they don't mind trimming it.
We have other liners that are not so squishy, and we did not lie to the computer about their thicknesses.