The main problem is the amount of 
quanta you need both to play expensive nymphs and to draw cards. In fact a deck like this is most effective with a little fewer hourglasses and more pillars.
If you have a FG with 12 HGs and 12 Golden Nymphs, and add a heckuva lot of towers, and go over the 30 (60) card minimum deck size, you get the potential to draw 26 towers in a turn. Since you get towers as you draw with your HGs, they effectively pay for themselves. So with that level of draw power, 3x mark, and my proposed 56 towers, quanta will not be an issue.
Of course drawing power gives you also a potential to draw a lot of pillars. The problem is, you need a lot of pillars in the beginning to start everything quickly, and you need even more later to play 2-3 cards each turn, so from my research I conclude a ratio of around 2/3 of your deck should be pillars or pendulums. This can be achieved in two ways. Either making a big deck, or taking less non-pillar cards. If your main concern is to make a deck with 6 hourglasses and 6 nymphs (x2 for FG) then it needs to be big to be effective. On the other hand, if you reduce the amount of hourglasses, you get a reliable 30 card deck which might be a bit less epic, but will be even more effective.
So it's a simple choice, whether we want to make a bit more epic but easier FG, or a bit harder but less epic
In case of FGs I guess there is nothing wrong with taking the epic route, but a player who wants an effective deck should probably choose the 30 card variant.
Now, imagine playing a Fractal + Mind Gate deck against Quicksilver, board full of hourglasses and nymphs on both sides
And of course the x3 mark and double draw means a FG might need a different pillar ratio, but it's hard for me to research that ;]
