Gutenberg: embedding a YouTube video

I’ve just activated the Gutenberg plugin. I’m using the latest versions of WordPress and Genesis by StudioPress.

I’ve been trying to embed a YouTube video in a new post. I’m using the YouTube block and I’m running up against three problems.

1. I can’t find a way of setting the size of the embedded video.

2. When I align the block left, the ratio of the video panel changes to square and again I can’t find a setting to adjust this.

3. Unlike with embedded images, there is no margin to separate the video panel from the text that flows around it. With the Classic editor, I have added the following code to my CSS style sheet:

#video-wrap {
float: left;
margin: 0 20px 5px 0;
}

What code do I need to use for Gutenberg?

All suggestions much appreciated.

PS The link to my website is to the home page. I have not yet published a post with the Gutenberg editor.

The page I need help with: [log in to see the link]