I'd say definitely upgrade the novas first. 2 guaranteed quanta of every element is equivalent to 23 turns of a quantum tower. Very worth it.
I'd replace the novas with quantum pillars, but if it's working for you, by all means keep doing what you're doing.
Upgrade the otyughs when you can, 5 health is just much more useful. If you have it, replace the golden dragon with a miracle (at least for me, it helped a lot against early rushes and abundant poison counters). You can get all the damage you need from the druid+firefly queen
There's one big problem with your deck: You only have 2 cards that can heal you in 39. You'll draw either the SoG or nymph every ~18 cards, so on average you'll get one of them around your 10th turn. that's very late in the game. You'll be long dead to a fast rush by then.
The solution: First of all, 2 hourglasses, preferably upgraded if at all possible. They make an enormous difference in decks over 30-35 cards, especially in a rainbow that has many parts necessary to function well. Try using a butterfly effect instead of a pulverizer. The otyughs won't compete with it for quanta, your mark can help fuel it, you can use it's effect the turn you play it (provided the creature you're playing it on has been in place since before the start of your turn), and it won't compete with the eternity for space. PLUS, if you add a quintessence, you have have an immortal pulverizor, of sorts, and a protected eternity at the same time.
If you find the maxwell's demon helps a lot, then keep it, but I imagine that a lot of the time it's just a dead card. I don't think you need the novas or demon. Try taking them out, and adding a pillar or three if you're low on quanta.
The sundial's really out of place there. If you draw it early, it would benefit you MUCH more to have drawn an hourglass and be able to get through your deck literally twice as quickly. Your style of rainbow focuses on creating mutants/eating enemy creatures for damage and control respectively, so you need at least four cards (otyugh+quintessence, queen, druid, bonewall) or more (additional quintessences, a boneyard or two) for your basic combo. You'll have to go through a lot of your deck to get them, so try getting rid of extra cards, and replacing them with hourglasses/pillars. You want 2-3 hourglasses and just enough pillars that you can play cards just soon enough, but not too soon, and also (almost) never have to discard a card. make sure to play your deck at least 10, if not 15 or 20 times, before deciding if you're over- or under- producing quanta. It won't show for certain until you've played many games.
Otherwise, a very traditional rainbow. Looks good to me, just try slimming it down a little more. To summarize:
-novas
-demon
-sundial
-dragon
+miracle if you have it, or maybe hope, though I don't think that's a good idea, since you have bone wall, but if it collapses, this will give you a second chance with your queen
+2 to 3 hourglasses
+pillars (to taste)
+shards of gratitude (3 to 4, if you can) or empathetic bonds (2's good). the bonds instead of shards will lower your iwn percentage considerably, since you'll have no way of really healing until you have your firefly queen out, but that's a risk you can choose to take. It will give you elemental masteries the vast majority of the time, when you do win.
+supernovas (4 to 6) as soon as you can. these really really help, since with unupgraded cards in a rainbow, getting that extra 2 quanta lets you get those cards out 2-3 turns earlier.
Hope this helps
