1: Never, ever, allow or in any way provide for "autoplay" on any individual youtube video, embedded or on-site. It's 100% user-hostile. No youtube video should ever, ever play in any wise unless the user actively clicks that triangle icon. No autostart, no hover-start, no timing start. Only if the user specifically says start, or, in the case of a playlist, if the user clearly and unequivocally and in a fully informed manner says to play the playlist.
2: If the user hits that "play" icon, put up a yes / no dialog that says "Would you like to view an ad on [insert concise description of ad's nature here]
3a: If user indicates yes, play the ad, still allowing for cancel, then play the video
3b: If user indicates no, just play the video.
4: Never EVER cover any part of the actual video with advertising interference such as banners, pop-ups, and so on.
I give Google / Youtube my permission to describe my plan, which I gift to them without reservation of any rights to income, as both "theirs" and "not being evil."