What I have found is that when it comes to sheet metal your going to want to use a few different avenues.  The attacher seems to be the easiest to start with but design line and multi point fill can be vary useful.  It takes a while but setting up your services and specs accordingly along with your button mapping is going to make design line work the way you want it to.  Making sure your buttons are in the right order and knowing what and when to exclude is a must.  Another thing that is overlooked is you can actually add a design line  to a line of duct or pipe.

The multi point fill is something that I haven't really used much at all but thing will come in handy as well. 

This is like hybrid of attacher and design. 

Hope this helps