I don't use Catia on daily (or monthly) basis, so I don't know this.
I have a few questions.

-when adding screws to the assembly is there a way of adding the holes too, at the same time. For example; you have two plates in the assembly, and you just want to drop a screw in there, with holes and everything....

-is there a way to set a standard clearance around a component. For example; if you drop a standard bushing, in the assembly, and you want certain clearance around the head.....

Pointing me in the right place to get the answer would help too