As I noted, I don't see any effect at 200% either.
Maybe this isn't the proper method to accomplish what I'm trying to do anyway. I have dng files that have been corrected/finished in CR, saved and the changes show up in the thumbnails. I now want to end up with sharpened web ready jpgs with watermarks, so that these can be sent to the web designer to post. The last batch were opened in camera raw and I set the sharpening to screen/high and hit Done. Then, I opened them in PS, added the watermarks and ran Dr. Brown's 123 process using 800 pixels width and bicubic-sharper to make the jpgs.
Any comments, corrections or suggestions would be appreciated.
Jonathan