I didn't realize this was on the list of fixes for the 64bit version!

I downloaded the 64bit version (1788) and the problems seem to have been fixed. The delay has been greatly reduced if not completely eliminated. I'm also no longer seeing extra WM_DRAWCLIPBOARD messages. Running side-by-side with the 32bit version (1774), the 64bit version is much better.

I'm keeping my fingers crossed that it will stay this way. Thank you for addressing this!