I'm an asshole.
I've been pulling my hair out trying to get the sync level correct for my Omega. The absolute best picture I could get still had some flickering. Just when I was about to give up last night and accept that it's the best I'll achieve I decided to try out another TV in my house...PERFECT SYNC.
Just wanted to post this cautionary tale for someone else who might have the same issue, I know I searched around for people with similar sync issues. Not sure what processing on that TV could be causing the issue (it's already set to game mode). Doesn't matter though as I only had it hooked up there for some quick testing, the main panel I'd use is the one that does sync up perfectly.
I'm an asshole too! I was having the same problems with an LG HDTV + Omega CMVS (I mean random flickering and even sometimes lose of sync), when I read your post I moved the only other TV I have in my home, a tiny 19 inch Panasonic HDTV, and played for a couple of hours without issues
Time to buy a new HDTV set
As for my settings with the Omega:
Zoom Setting: Normal 2 (to preserve the source's pixel ratio)
Processing mode: Picture (probably the best for 240p signals)
Brightness: 20
A/D level: 140
Sync: ON (to avoid the stutter and lock the Omega to the native 59.18hz refresh rate)
Sync level: 19
720p60