>>5207178This. When filming things like Ultraman or Sentai mech battles, one of the cardinal rules is that you never, ever show the stage floor or feet. It kills the illusion of size.
>>5207183I don't know about any instruction manuals or anything, but last year NHK World did a documentary for Godzilla's 60th Anniversary that includes a lot of info on how toku filming works, and goes into things like perspective and shot composition using the filming of an episode of Ultraman Ginga as an example. It's a great documentary, and a really informative watch if you're into kaiju films and tokusatsu.
http://www.dailymotion.com/video/x27beeq_godzilla-s-60th-anniversary-the-amazing-world-of-japanese-special-effects_creation 