"Currently with this and a couple of other operations, I have to modify 3-4 different parts to get the one length change that I want instead of doing one length change."
For those who have a similar problem description I suggest the use of layouts.
They seem kind of awkward, but are a great solution where a bunch of parts/assemblies need to be coordinated about some set of dimensions. If you haven't used them, they are like a cocktail napkin with a crummy sketch and some dimensions. You refer to those dimensions via relations in other parts and tie all those dimensions together without tying the parts to each other or to some skeleton. Big advantage - the sketches are not to scale, so you can have a 1/32 hole 1/2 inch away from the end of a 10 mile long tube and see it. And you can add comments - add text and you can tell what the thing is for, unlike most all the rest of PTC software.
Many times, creating a layout should precede any other model making for complicate items.