With the Cobra I found the best way with water is to just add it to the blast baffle..So just a gob of gel on one side would be just as good for long term storage..Dunking the can makes it sound okay but not nearly as good as when you add it to the blast baffle..My Mulitmount with oil (they say no to water) makes no difference what so ever for sound..It just smokes..
The odd thing about the Cobras wet is reapeatability..sometimes it can be hollywood quiet and other times just okay..Tipping the can at about 45 degrees and shooting in 5cc's of water the same way still gets different results..Usually good though..
Here's mine in .45 shooting 9mm through it..I'm shooting .22 next to it for sound comparison..This was the 5th string I did..The one after this was not nearly as good..
I have to get some wire pulling gel..Haven't tried it yet..
Guess part of the point of this is baffle design is going to play a part in which would be the best way to add an ablative..http://www.youtube.com/watch?v=Ivg5X92oGv4