If you can get Omniscience into play - chances are, you've won that turn or the next one with your deck built right.
If not, you're doing it wrong.
I wouldn't worry about protecting Omniscience.
The card is hard to get into play without devoting the entire deck to it, so be mindful that some games your draw will just screw you and you'll get stomped out.
I run a mono-blue deck with about 12 filter (ponder, preordain & brainstorm), 8 counter, Dream Halls
Digging in Ancestral Knowledge
, but if you have money for fetchlands - you could try Lim-Dul's Vault
When I cast Conflux (usually on turn 5, sometime turn 4 with Saprazzan Skerry or Lotus Petal ),
I fetch; Conflux
, to be discarded for Omniscience
, Underworld Dreams
, which I then target with Oblivion Ring Worldfire
When Worldfire hits, Underworld Dreams comes back into play.
Dream Halls can be used by any player though - chances are someone playing blue will discard a blue card and cast a counter, so you could potentially wait until the next turn to cast Conflux with counter backup (if you wanted to, but be prepared to lose you Halls or have your opponents put down ALL their win-con's in one round)
With Dream Halls, there are HEAPS of different ways you can build your win-con, including playing Nicol Bolas, Obliterate
& Liliana Vess
together with Wheel of Sun and Moon
I generally change this deck often to make it interesting....
There is a quicker way to do it, Show and Tell
If you're suggesting Entomb, I'm assuming you've got a bit of cash to spend on this deck?(cos this way ain't cheap! - and it's not my idea either I should stress.)
Pack about 4 to 6 creature targets like Griselbrand
& Emrakul, the Aeon's Torn
, Omni, 12 filter (ponder, preordain, brainstorm) and then you'll need 3 Show and Tell
(1 outside the game) with 4 Burning Wish
and about 8 counter.
Omni is the card you want to use with SnT if possible.
Once Omni is in play, the cards outside the game that are useful could be; Eye of Nowhere Petals of Insight Grapeshot Time of Need
and of course your 4th SnT.
The idea is centered on Show and Tell. Ideally you want to find Omniscience
, but one of your fatties will also do.
Like Dream Halls, Show and Tell also has a weakness, being completely reliant on one card (counter it!!!!)
If your opponents are packing Angel of Despair
, Oblivion Ring
etc., or some other "When enters the battlefield" text that hoses your win-con's, you're gonna be filtering through your deck for a while trying to find your pieces to get going again.
The other way using the cards out side the game, is once Omni hits the table, cast burning wish for Petals of Insight
. Repeat until your Storm count is big enough to frustrate the table, and you find another Burnng Wish, play it, finding Grapeshot.
Note the arcane interaction between Eye & Petals too. Good Luck keeping friends playing a deck like this.....
On that, good luck keeping friends playing an Omniscience before turn 5 in any build!!