I don't think that actually there is a sort of
general rule for this but in my very personal opinion you (simply) have to
warm up the YT channel and so your daily post number until you reach more or less - less is better - 20 new videos per day.
For example, start with 1 video day 1, 2 videos day 2, 4 videos day 3, 8 videos day 4 etc.
Don't just simply double the amount every single day, try to make it a little bit more random +/- 1/2 vids/day.
By the way, just to make a point, this is just my personal opinion, let me know if this works but I don't see why it should not work.
All the best,
DGH