Do I need to wrap shortcode parameters to double quotes or single quotes?
No. I even suggest to you avoid wrapping shortcode parameters to double/single quotes to prevent broken output when some plugins modify content with nasty filters.
Just avoid empty space between ID’s.
Is there any way to make the pop up player any bigger?
You can use custom style with following selector and a rule:
.ytc-mfp-container.ytc-mfp-iframe-holder .ytc-mfp-content {
max-width: 1200px;
}Just set preferred popup max width in pixels.