Air/Gelatin/pigment - doesn't really matter - but just 2 mins wont make much difference, the best thing is to rotate the paint over the previous few days, then when you are potting up thoroughly mix it up with your hand and not over pack pots.
RainX rocks on barrels. clean out the barrel with alcohol to get rid of all old gelatin, then thoroughly dampen a bit if tissue and push it through with a bit of dowel. Leave it to dry overnight then lightly polish it with a furry stick type - nothing realy tight. works wonders I tell ya'