how small is too small to create estimates?

For the most part, it is for you to decide -- since you are in academia, you need to figure out what is "passable" with reviewers and editors. In more practical terms, you would need to see what kind of impact the precision of your estimates and/or the power of your tests have on the stability / defensibility of your findings.

For most practical reasons, the sample of 1000 is plenty. Most political polls end up with that sample size, and are entirely content with that.

Are you sure 941 is the *actual* frequency, not the weighted total (which would then be based on a much smaller number like 20 or 30)?

For the most part, it is for you to decide -- since you are in academia, you need to figure out what is "passable" with reviewers and editors. In more practical terms, you would need to see what kind of impact the precision of your estimates and/or the power of your tests have on the stability / defensibility of your findings.

For most practical reasons, the sample of 1000 is plenty. Most political polls end up with that sample size, and are entirely content with that.

Are you sure 941 is the *actual* frequency, not the weighted total (which would then be based on a much smaller number like 20 or 30)?