Thanks guys I got in touch with Monstermakers (thanks for getting back with me.) and it looks like I was mis-informed about the size. Theirs should work nicely.
As far as cost of a lifecast, most of the time it is ALOT more money to do one of those. Usually costing in the neighborhood of $250 or more to have someone do it or possibly less if they are working for free and only materials costs come into play. Still it is well over $100 to do it right.
I have a technique to do one (I did a 1/2 face mask years ago) and it turned out as good as needed. It doesn't have the detail but still works. I just didn't want to take the time and put it on something that I could just buy.
Thanks again to all that answered in this thread and a big thanks to Monster Makers and your help.