The reason people ask for dripfeed (or vice versa don't order them as often as they could) is that it is just too much of a bump.
I have no problem ordering 10k twitter followers - but anything more than 100 per day is suspicious. Ordering 1k in batches will do bumps to anybody who looks at it.
I am happy to take a delievery time of 10 days for a 1000 delivery. However those - if not setup properly - will show up to anybody checking the followers. Same for instagram - those profiles are problematic as soon as somebody looks into the followers.
Give me a maximum of 200 a day and I'll order 6000 right away. If I have to do it by hand, 3x1000 I am likely not to do it at all.
Btw I would like to see an account where you have added followers to see how the follower look, please do pm me if you have something like that, thx. Happy to do a review of a small batch of twitter followers or other on one of my experimental accounts.