I use 209's with my Omega and they work fine, although I think I am getting more out of the FFFG loose powder per grain... Are the sticks FFG, I can't remember, I was shooting a buddies... Have you tried the loose powder, maybe that will help.

I am surprised that a 209 would alter the accuracy. It is only the primer, it shouldn't really affect it.

Don't you just love AP, it is so clean!!! I haven't had any problems with mine in humid conditions either... Just love the stuff!