Enrollment for 5a is 2090 and up. 4a is 1005 to 2089. 3a is 450 to 1004. 2a is 200 to 449. 1a is 199 and below. Six-man is 100 and below.
http://www.uiltexas.org/files/alignments/Conference_Cutoff_Numbers_2012.pdf
Yeah, I caught that myself earlier and dutifully sent out my mea culpa...I was saying 4A and meaning 3A.
Thanks for digging out the real numbers and getting them posted.