Lets find out.
I always start off doing one HDR Merge and checking my settings before going off and doing a load, in this case 22.
Unfortunately the HDR Merge Preview got stuck - I decided to use Deghost, but it turns out there is no neeed. Once Lightroom has woken up from its slumbers I checked the Deghost overlay box and there was nothing there so will now have a go as doing 22 HDR Merges at once.
I will report back once I have got all 22 running.
Rick McEvoy Photography - Adventures in Lightroom (there was once a book called that!)