I only started my gold Olympus habitats after I had my gold shrines. I now have 8 Olympus habitats with a total of 24 gold Olympus dragons. As you have discovered the panlong army are the fastest earners, but for me I need to check in every half hour to reap the rewards.
I have 3 rainbow and 3 leap year dragons. I have sun and moon dragons, but these are in my hibernation cave as the blue moon solstice and lunar and solar eclipse earn higher money, so they occupy my sun and moon habitats.
It's really difficult when you are working toward your shrines as you can't afford to sell off dragons that are at level 10 and above, because if you do, you may need to do that process again a little further down the track,and that costs further $ for treats.
The key to success is not spending gems on speeding up breeding, but rather spending them to increase the capacity of your hibernation cave.
Panlongs are the best dragons to feed as they count towards 4 shrines because they contain four elements in them. Always work towards feeding your hybrids first.
Don't sell off dragons you may need later. And as to the Olympus habitat you only need to have one with 3 gold Olympus dragons in it, and you will see huge results with your $ earnings. O, and when I'm not trying to breed for any dragons because there is nothing new to go for, I breed rust and rust and magnetic and magnetic for $

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