Another thing that might work (I hope someone will correct me if I'm wrong) is to take your chances with the 24-hour check-in. If you get a poor boarding group, you can try upgrading one person to the A-list which would give you an A1-15 spot. That person (it sounds like it would be your wife) can board first and grab 3 seats together (I would put bags on the seats so they don't appear "available.") While SW technically doesn't condone seat saving, I've done it numerous times (admittedly with only one seat) and never had an issue. If someone asks you if a seat is available, you just say no. And the A-list availability isn't guaranteed. But it is another option.
With the number of EBCIs being increased (with the new way that fares are broken out and the fact that SW credit card members get a certain number free), I fear that the days of the 24-hour check-ins getting mid-As is past. However, I did check in two minutes passed the time for my flight last week, got C13, and still got an exit row seat. It probably helped that I was a solo traveler, but it did make me want to go out and buy a lottery ticket.