Gary, I made the video the size it is above because any size larger and YouTube puts a ‘Watch on YouTube’ button allowing your visitor to leave your website. Using the video above, they do however have the ability to enlarge the video to full screen on their monitor.
Now, I can make the video display larger here upon arriving if you don’t mind that the visitor then has the option to leave your site to go watch it. In that case though, they won’t end up on your home page where you wan them. See below where I increased the size just a tiny bit … the option to leave in lower left displays automatically: