How does one guage the size of the decal vs. the size of the model in order to get the best looking decal?
The size of the model is the largest number of pixels that it will cover in any movie you make with it. Generally, you should have a concept when building a model of whether it’s going to be used for long-shots (very little detail necessary) or medium, or super-close-ups or what. As an example, on the Brawl pages (http://www.tmn.com/~albasch/Brawl/) (plug!, plug!), my Keitoshi character was built for medium-close action in an NTSC resolution setup. So, she looks OK at 400×200 (the large shot on her particular page) but looks much better at 200×100 (the icon picture on the main page). ‘Course, this has nothing to do with the decals, but rather is an issue of spline density. But the same principles do apply to decals.