I think you are going to make a fine personal view to the subject! You've got really helpful tips there above. I suggest one quite easy and fast function to combine two layers - use the Quick mask function. I hope these instructions I made will help you. I made this with my on photos - and if you have questions, please feel free to ask them :-) Sorry if you don't use PS, I can't give any advice with QM - maybe somebody else know how it works in PaintShopPro or in other apps.