3 flygon delta 3-3 altaria why rayquaza? takes up room, (not much but...)Well I suggest this deck:
4-2-3 Flygon ex delta also 2 flygon delta(Not ex) metal grass
1 rayquazza ex delta
4-holon's castform
2-2 altaria ex
The last combo really depends on what you are wanting to do, I can't neccisarily tell you what to do with the deck, you might look into exxecutor delta species line, a lot of deck building is completely deck preference. Flygon is an amazing deck, but it has to be run right.