Thank Alex, I hope for the best :-)
Ken,
My concern at the moment are corrections..
On images of
M42 I took some time ago, stars in the centre of the frame are acceptable for both with or without FR.
However, in corners (APS) without FR, there is a bit of coma (which is expected) but with FR they are quite distorted, almost as if field curvature is bad. And that distortion somehow doesn't look anything like Baader images...
I haven't done much about this problem since then (mainly because the investigation of this could be quite tedious and my observatory was still in plans..), but now I would like to sort it properly.