It is possible to get a job on Citations with less than 1000 hours; but the key is networking. I wouldn't count on it, as in put all of my eggs in that basket. I would get my CFI, instruct and if you get a Citation job - awesome.
With regards to instructors; my advice would be to go visit each of the schools personally (if you are in a position to do so) and get a feel for them. And most importantly; talk to the students (not just the admissions people). They will tell you about any serious problems or issues they may have had or are having with the school.