Good news. Got a call from my friendly neighbourhood watch repairman. He finally got the stem tube and crown for the watch. Went to have a look and liked what I saw. The crown was a large as the original. Both the stem and crown are Swiss made and are sterile (unsigned). However I can only get my watch back on Friday as he has to bore the case to fit the new stem tube as the new stem tube has a larger outer diameter as compared to the old stem tube. Also the new stem tube is thicker. He will also pressure test the case after everything is done. I asked him to pressure test up to 300 M. Hope to post the completion of the modification soon.