I had a mate make up a restraint for the Pl16803 camera and optic train. The image is below. There is still slight flexure in the wood as the mount tracks. We are talking in microns here. I will get an adjustable version made out of aluminium and teflon pads. This mounts to the robust dovetail that holds the the whole image train.
NGC6188 X1.5 native size 7MB
http://d1355990.i49.quadrahosting.co...GC6188_NII.jpg
M16 and M17 mosaic 5MB
http://d1355990.i49.quadrahosting.co...16&M17_NII.jpg
It looks like the corner star issues are all down to flexure not the optic. It was far worse with my system because of the weight and size of the CFW.
Bert