I was comparing my newest run with the new run from Wailmernoir (both are up on Youtube) to see what we did differently, and I thought this might be fun to share. Sorry about the messy audio, these are recorded from our twitch streams, so we're both talking a bit.

I think you have to hit play on each one, then it will pause and wait for you to hit the play button at the bottom, and it should be pretty well synchronized.

https://viewsync.net/watch?v=ojKOi98MK0Q&t=4.34&v=oPDl69UJyrg&t=1.79&mode=solo