Brady
There is a lot more , you need to condition through out , if you don't want to use live food because of the risk involve, make sure the food is rich in proteins, ie beef heart mix, sea food mix, freeze dried black worms, vitamin enrichment etc. WC regimen " daily" so grow and health is guarantee.
For the water quality and temperature it doesn't have to be really cold , is just relative cooler , you are trying to imitate a rainy season for ie a water temperature in the low 70 to a high 60's will cause a temp drop in a normal discus tank temperature of 82 or more.
The other factor is water hardness and ph, with the GH being more important to trigger and get the eggs fertilized a TDS between 50- 100 is good for breeding domestics . I normally shoot for 60 to 70 , just think about those years when music was really good , lol, just kidding. I don't really worry about ph it will take care of itself if you watch your water hardness.
There are many other factors to consider but this is what I can think right away.
Another thing 6 is what probabilities tell us for a random pick, but sometimes people influence the results by choosing the bigger fish, or the red ones etc and you might end up with all males in case of the big ones, or all females like in the later .