i think waitlists are something that can vary *wildly* from school to school :-/
some schools may have 30-50+ people on their waitlist, and some, like UF, generally limit it to 20. however, being number 6 on the waitlist sounds extremely good to me 🙂 and i honestly think the chances of 6 people declining their positions are high. i know at UF, they send out like 15ish acceptances for out of staters, and yet the final class is only ever made up of like 7-8 out of staters. so there you have at least 6-7 spots. UF won't tell me what number i am on their alternate list, i could only hope to be number 6!!!
anyway, everyone ive talked to said that being on a waitlist is generally a pretty good thing, so try not to worry too much!
good luck!!!!