You don't need to glue the magnet you can just put it against the jar or under the jar. I guess If you want to make it permanent then go ahead and glue it.
I would personally use at least a 1/2 inch thick neodymium magnet to have good penetration of gauss to the jar. Around 5 minutes should be good.
I actually think magnetizing the distilled water before making the coilloidal silver might make better smaller particles. There was an article I had read recently about this but can't find it at the moment.
Thanks for the video, it showed that water is affected by magnets. There are other videos that show that water is affected by music, positive/negative thoughts, words, etc... very interesting stuff.