Availability right now is:
AC 1980 (0840), a 736: J9 C9 D9 Z9 P9 R9 Y9 B9 M9 U9 H9 Q9 V9 W9 G9 S9 T9 L9 A9 K9
AC 1982 (2020), a 319: J9 C9 D9 Z9 P9 R6 Y9 B9 M9 U9 H9 Q9 V9 W9 G9 S9 T9 L9 A9 K8
I've never put in a cash bid on an upgrade (I personally would not spend $50 on it, and it has never been that low), so I can't comment.
But route, IME flying south Sundays, returning the Thursday/Friday midnight-ish flight is that it goes from 50% load to totally full, at least on the '319. I have no idea about Wednesdays, but its something to consider.