It shouldn't be hard to do 100 HITs a day, during your 10 day probation. Of course, if you're trying to catch great HITs and do stuff that's got decent pay, it can take significantly longer. Getting numbers and making a decent amount per day are separate goals that don't always work together because, to get numbers safely and quickly, you may be doing penny HITs. So, in the beginning, before you hit those milestones, you may have to make the choice of numbers or income.
But, 1000 should be easily achievable in the first 10 or 11 days. If it's not, it's usually because people are expecting to make more and disregard the numbers HITs that they should be doing when they start because they don't pay well enough. That is true but, it's just like being a lightly paid intern where, sometimes you have to make the choice between experience and income.
The max(3800 a day) is achievable with the right batch. 100 a day is easy. So, in that case 1000 in 10 days and 5000 in 50 is easy. If you do more, it can happen much quicker.