Nothing to worry about man. Ill help anyway I can.. from way over here. lol
But first! I have to tell you, Im loving your sense of humor! From the Dos Equis reference to my favorite Elmer Fudd episode, awesome, lol.
I jumped into my helmet headfirst and it turned out great, well I think so anyway. If you are making a mold, then other than making sure it is the right size for you, and that Jun helmet for sure is, dont think of it as anything but a tool.
Ill never wear the one I used for a prototype again because it doesnt fit over my head anymore and Im going to keep it to make a new mold if I need to at any point in the future. I made it a very basic ODST bondoed out purposely made with minimal details for personalization of individual castings later.
It was sanded very smooth and came out of the mold with little difficulty. You DO want to make sure that the original is reinforced well - FROM THE INSIDE - because taking the rubber/latex mold off of the helmet will put a lot of stress on it and you do not want it to crack/smash or otherwise become damaged.
I had painted my original and clear coated it. Not sure if this was necessary, but it came out of the mold easy with very little flaking/sticking to the rubber.
Maybe this is the best way to state my theory on this - DO everything to your helmet before making the mold that you do not want to repeat on each casting. If you want a smooth, realistic looking helmet, make it so before making the mold. It will save you tons of work on each successful pull.
I followed BenStreepers vids and they worked great. Im far from an expert on armor making and I did just fine. You seem to have quite some talent for it and it is good to see you worry about the end product, but you are going to do a great job man.
I would use bondo for sure on the outside of the helm and smooth it out so it will come out of the mold easier. Easier to work with than rondo too.
Just keep going at it, I bet you will impress yourself.
My favorite part...the demo of the file.
