Too thick and it's difficult to squeeze out, but too thin and it will drip and your candy will sag. Note you'll want to play with the viscosity of the icing. You can use a pastry bag, but I find it easier to use a squeezy bottle from a craft store, much like a diner ketchup bottle with a conical, pointy tip.
I prefer a mix of powdered sugar, water, and meringue powder. Mix up some icing - again, there are plenty of recipes on-line. Of course you can get entire packages, but you might find you don't use a lot of each candy/food. youre missing Lusankya (escorted by a pair of ISDs and a VSD, according to The Bacta War), Guardian, and Knight Hammer. the logistical train must be a f-ing nightmare.
I recommend going to the bulk section of your local grocery store, and getting 'handfuls' of a variety of candies (or crackers, or any dry food) to experiment with. 1 Eclipse-class Super Star Destroyer, 6 Executor-class Super Star Destroyers, 17 Imperial-class Star Destroyers, 1 Victory-class Star Destroyer, and 6 Strike-class Medium Cruisers. I used a variety of candies, including candy canes, cinnamon red hots, licorice balls, gum drops, candy from a candy necklace, candy-coated sunflower seeds, and a 'coke bottle' for the captured Tantive IV. You can decorate as much or as little to suit your taste. While the Star Destroyer should be relatively complete prior to this step, it's the decoration that gives it a sense of scale and whimsy.
