rkontra,
So if I'm understanding your post correctly, you've got an ipart that you've uploaded to content center and you want to be able to place it and then manipulate it to fit your needs through a form you've created in the part. While so long as the part is placed "As Custom", I don't see why this wouldn't work, I don't believe it is typically the route taken.
Typically you'll set up your key parameters (eg Size-1, Thickness-1, Size-2, Thickness-2, Length) in content center by editing the Family Table. This is by going through the ribbon Manage tab, Editor, RMB the part family icon, select "Family Table". By doing it like this, you make it so that when the part is placed, the parameters are specified before the part is even created. If placed "As Custom", a custom name can be given as well as save location and any changes (either via "Change Size" or by editing the part) will all be local. Otherwise, if placed "As Standard", the part will be saved in the content center libraries under the name determined by the naming scheme in the Family Table but this part will not be editable via opening/editing the part. Any changes made through "Change Size" will create a new file in the content center libraries. As much as that may sound like extra clutter, this actually consumes less memory in the long run if the part is used often enough.
Hope this helps and have a great day.
