My understanding is that youtube is best to do 16:9 on because you don't get black bars (top bottom). But some find that appealing. But obviously you can just add those.
3:2 and 4:3 is going to have them. I don't see the point in shooting like that. It's vine tier aspect ratio choice. It looks terrible on YouTube.

Any specifics about the project?

Also I'm uneducated, I've just played around with server-side video processing and done a few crappy youtube videos. Best video has 11k in 7 years lol.

>>16915141
I was thinking that. I tried a test video in 3:2 and it was sort of boxed in. I suppose it made people view it in wide screen to get the best experience of it.

It's just a short horror thing. I studied film a few years ago and kind of fell away from it with other stuff taking up all my time. I'm going to get back into making shorts, but I'm starting with something easy.
One location, minimum dialogue and two actors. Pretty simple stuff.

>>16915155
Ok. I think that most people who do horror mainly do narrow shots. That's the impression I have. So you want 16:9 most likely (because 4:3 is just ugly so it's not an option) but I find movies that don't follow such conventions to be much more interesting. A wider aspect ratio could be more interesting. More engaging because you're not as used to it. Might even make the impression of he world different. Should probably do some testing and consider this a bit.
I don't know any of the terminology so I can't express what I find appealing well. But my impression of most artsy educations is to teach you what works and what doesn't. It's your excursions into the unknown that are interesting.