I know there’s that “sweet spot” range of 700-1.3k words, but I think some of it comes down to writing style and story, too.
As a reader, I’ll read any length episodes - one page/update, nine pages/update, whatever. I think it’s more important to focus on where the episode cuts off. As a writer, it’s not always easy to find that spot. I wrote my story before even considering posting it and I have some scenes that are a quarter of a page and some scenes that are 12 pages long. So, trying to find a comfortable break point means that I have episodes ranging from 450 words all the way up to 1.8k words. It just depends on what’s going on. But this is something I’ve found works for me. I don’t think there is a single correct answer. There’s a lot of various options that should work well for you.
I do agree with what everyone else has been saying about frequent uploads. That does seem to be important.