In a sixty gallon tank your discus are going to be crowded in the not too distant future. For six discus I would put them in a one hundred gallon tank. Remember a full grown discus can easily get to eight inches and with their body shape that is a lot of tank space.

Also another thought the bigger the fish the more waste, the more waste the more cleaning process. It sounds like you have found your love...Discus. I really can relate to you. They are beautiful fish and graceful. If you decide to get the 6th one before they reach their maturity, maybe you should consider getting a larger tank for your ever growing enthusiam. You need to post a photo of your lovely Discus. What color are they? I would love to see them and I am sure the others would too.
Theresa