A week or two isn’t going to hurt if it’s to support the author that’s actually making the story, not uploading it. It’s easy for us to say, “oh just a couple days” but if it was your own work and was trying to make a living with it, I think it would be a different response.
Anything is better than the day of the author’s upload but I say weeks to really ensure they do.
The uploader isn’t the one creating it. It might seem harmless to just immediately add a chapter but if you took in consideration the artist who actually spent the time and money to create it that a couple weeks isn’t hard. So, to be honest, just letting the uploader “do what they want” as an answer personally doesn’t seem to me like one from someone that doesn’t appreciate the artist and what they do.
Thank you uploader for the chapter!
However, I would wait a couple of weeks before uploading the next chapter to allow the author to make money on the official site. Both us reading it here and the author will benefit from it. Just ensures we are allowing the author to be able to continue this work. :)