Thanks for the input all
Though Ive imaged this plenty of times in the past, I really did want to try and get a nice deep image, on a night with no wind to buffet the scope and reasonably good seeing.
I think Id rate only M42 as a more difficult object to image in its entirety, that is to show detail in the brightest, and faintest parts.
The OAG was using one of the stars in the nearby Triffid Nebula as a guidestar.
Scott