Agree with sabot loader on the JB bore paste. My experience with Omega's is that they will shoot a wide range of bullets including the XTP and especially the 250 grain Deep Curl and SST and Shock Wave. The ones I have had experience with always shot best between 90 and 110 grains of Blackhorn. The bores have varied but usually would except the smooth Harvester after bore pasting, some times it is necessary to go to the crush rib.I would suggest starting with a 100 grain load and trying both the 90 and the 110 load after sighting in. You will probably fine that the Shock Wave is the most accurate as far as tight groups is concerned if you should decide to use them I recommend the bonded one for hunting large game. Try both the 250 and 300grain I normally fine the 250 most accurate but a lot of people have found the 300 grain to be most accurate in there gun. The XTP is a usable bullet I used them for years and killed a lot of deer with them I did find that using a bonded bullet like the Deep Curl or the Bonded Shock Wave makes tracking easier because of the consistent exit hole.
If you chose to go to the expensive bullets the Lehigh is the best but I like the Shock Waves because I can practice with the cheaper bullets and the bonded ones shoot into the same group.