Give my recipe a try. It is very fast drying and I rarely experience craters. It is also great when you are using light and dark shades together as it does not bleed. And it takes only a couple mins to make from start to finish.
The recipe is under Sugardeaux Quick Dry Royal Icing in the icing forum here.
I did give your recipe a try and it is the bomb!!! Love, love, love it!! NO CRATERS!!! Thank you for posting this Sugardeaux!!