I recently purchased a crystal installation tool and it is too small to be used for a 16s Pocket Watch. The guy I purchased it from was an old repair man and said that you can just push in the larger plastic crystals by hand. If this is true, could anyone comment and recommend the technique including whether you should do this with the ring off or screwed on the watch? This is the tool I purchased btw. Sent from my iPhone using Tapatalk