Home Studio does not include a lens manager or the ability to create or save lenses.
 
However, your comment prompted me to revisit lenses. HS provides some pre-defined lenses, and I think what's been happening is that some of my projects have selected "Basic" lens, some have selected "Advanced" lens and some have selected "None". This HAS TO explain why the different layouts.
 
I'm going to go through each project and set the lens to "None". I bet that will kill this problem once and for all.
 
Thanks for pushing me to look again at lenses, scook.