Forgive me if this has been covered already in this thread or another, to may posts to go through to check.
Using a pen to plug the hole for the jack when sealing it worked rather well for me. The pen fits pretty tight and I was able to add hot glue all around the jack and seal it up. Once it was set, but not all the way cool, I just twisted the pen out, which came out easily. Nice seal with no leakage into the jack.
Note that the first few times you take the plug in and out the little pegs that stick out of the jack will cut at the glue/silicone as they turn.
Nice! Thank you.