So we can help others too while helping myself, here's more useful information I found:
I read that adding the string &ap=%2526fmt%3D22 t both instances of the URL link within the embed video can allow for “HD (High Definition) Embed”, and for "High Quality Embed" use the string &ap=%2526fmt%3D18. I'm totally new at this so tried those and am not even sure there's a difference when I put all 3 videos side by side. Mine is both high quality and HD.
I also learned that adding &autoplay=1 (not dissimilar to your code) does indeed work in making a video autoplay.
So, we have 2 goals left (IF SOMEONE ELSE COULD CHIP IN, as you were suggesting too):
1. Some little code to make the video FULL SCREEN
2. How to ensure it autoplays before anything else on the page loads/shows. Again I use your basic html and I've never put a video on any of my pages, much less tried to go full screen, autoplay and onload. It's the onload part I'm asking for this #2. Thanks for your solutions.
Thanks. I'll be watching.
Off topic a bit, but still interesting, wanna get your honest opinions/experiences on the following:
If you turn off commenting and rating and captioning by others (on youtube or any of the 30+ social bookmarking sites I plan to link to the video, do you "lose the benefit" of having a youtube video as far as Google SERP benefits? I'm always afraid people/competitors will just start voting you down and making negative comments to sabotage you. Thanks for your thoughts.