I have on occasion made combined figures using rocket science, in cases where the clothes covered most of the original figure (superheroes are a good candidate for this). You may need only the person's head - the rest is covered by bodysuit, boots and gloves. However for more conventional clothing it's not so straightforward. Anyway. The large file sizes are almost certainly due to the morphs being included. If you're saving a finished character you probably don't need all of them. Try stripping them out using Morph Manager (free download from my site, if you don't have it).