When the term 'conforming clothing' is used in relation to Poser, it generally means that it poses with your figure, and does not refer the tightness or baggieness(?) of the clothing. Making baggy clothes uses the exacts same process as any other clothes, the difference basically is in how the clothing is originally modelled.

Rescaling and conforming clothes don't mix very well. With characters with built-in clothes such as the casual or business figures, you could easily make a heavy set character with some rescaling and a few magnets. However, with existing conforming clothing, this can be a real pain.

With Victoria2, these rules change a little bit. Someone is making an add-on pack for the existing Victoria Clothing Pack 1 allowing those articles to fit Vicky2's full-body morphs, that will be brokered at DAZ.

Hope this helps.