A quick first light with the flattener / reducer issues worked out...

Finally have all of the right parts in place, added a 40mm spacer between the W.O. 0.8x FF/FR II and the QHY-9.  The field looks much sharper now.  Instead of 20-30% of the field showing visible curvature, I figure maybe 5-10% of the field has any worth note, and even that portion has improvement so it's not terrible.  We're really only talking the extreme corners at this point.  Plus with the FOV I get anyway, cropping it out isn't a terrible loss.  A compromise I'm willing to accept.

Unfortunately I only squeezed out 9 subs x 150sec before I had to end my session.  Note that the moon was blazing away in the sky so between not having many subs and having the glowing orb of death making an impact, there's a pretty bad gradient in the background so I didn't push this image too hard.  I also was dealing with rediculously strong winds again so there's a slight elongation on the stars, but again it's minimal and should be a testament to how rigid the new rig is to be able to stand up to 40mph gusts.  I still have some issue with my flats that I don't have fully sorted out and plan to spend the weekend working on.  More to come on that topic.