If you make them into smart props at least you won't have to position them each time as they will automatically parent themselves. At first, import, position them and then parent them, usually boots should be parented to the shins not the feet. Now save them in your props library and when asked if you should save as a smart prop say yes. Test them before deleting the old ones! Many times I thought I had saved a prop which took me ages to position only to find that Poser hadn't saved it, upon opening the pp2 file I saw a blank page. Now I don't know how well props can be animated, a conforming figure will probably do better but at least you'll be able to use them in stills without going through all that hassle again.