I think the ingredients of the creme-like filling are still a trade secret but there is much urban lore that you can read up on the net. I just used a can of Whipped cream topping for this giant Twinkies. It comes with the injection applicator nozzle and is pressurized for easy application. Pick three spots on the top of the Twinkies cake to inject the whipping cream topping. You may have to probe a bit with the tip to enlarge the cavity where the filling goes. Like is says on the glue bottle, apply sparingly, whatever that means. When done, as like a real Twinkies, invert the entire cake so the molded part is now the top of the cake.
Voila, enjoy your giant Twinkies. Wrap it up in cellophane, pack it up in your lunch pail and take it to school to share as an afternoon snack.
Remember, after eating giant foods, be sure to brush with your
giant toothbrush.
I'm not trying to take anything away from your instructable. It's actually a very well done step by step. I just wanted to throw in my two cents:
http://allrecipes.com/recipe/homemade-twinkies/
this is for a twinkie copy cat recipe that I have made before. It's really, really, close to the original. So, basically use what you've done with an actual recipe. I hope you take this as a compliment to your instructable.