As noted above, 4 open at one time is almost like finding a unicorn.
The only time I've ever seen it is when I was looking into a South American trip and found 4 each on Avianca and Copa and this was right around 300+ days out.
Edit: If you see 2 you should take them as one booking and then do a separate waitlist reservation for the others. I've had this work out for me in the past.
Last edited by NoLaGent; Jul 6, 2017 at 9:22 am
Reason: edited to add booking tip.