First, I would shoota box or two oflead conicals through the Omega just to smooth it up a little. The T/C Shockwave sabots seem to seat about right in both of my Black Diamonds and Omega. Firm, but not so difficult you need a mallet. I think I would try those first. I also would try 100 gr. of powder, with each you are considering, and work up from there.

My pet sabotload is 130 grains of Pyrodex pellets with the 250 Shockwave. Others have reported good luck with 110 gr. of Triple 7. I know the pellets are expensive, but they shoot well and are fairly convenient. Good luck. Roskoe