RE: New to Muzzle loading
Welcome to muzzleloading! I'd ditto what some of the other guys said - it is worthwhile to take some time to play with different bullet/powder combinations and see what your Omega likes. While some people get good accuracy with the 150 grain loads, I think most of us here find a lot of times you are just wasting powder shooting that stout a load. It's hard on the shoulder too. However, once in awhile a certain rifle will like a higher powder charge and shoot better with it - it's hard to say.
If you have the time, I'd advise getting some loose 777, and a couple packs of different kinds of bullets to see what works well. If you don't have the time for it, 2 777 pellets and a 250 grain Shockwave will most likely provide accuracy and power that is more than good enough for hunting purposes.