I don't think that going under 180 days makes it a "gimme" medal, although to be honest I am not sure what you mean by "gimme" medal. My understanding of the SSM-NATO medal was that it was brought in the 90s to recognize the Germany folks. They probably went over 180 days to exclude "flyovers" and others not posted to Germany. This mission may well be 180 days, but it could be just under that limit for some folks. I do not see the point in being so strict - go with 90 days. If the SSM NATO is so sacred then by all means make a new medal. I do think, however, that troops who go abroad for this duration as part of the demonstration of national resolve should be recognized. Nobody would admit to this being important, but I figure that it should be ironed out.
Regarding the Bridge Demolition Guard video, the Brits always had the best training videos. I remember watching that one in the early 90s. I might just make my students watch it on the next Tut 2!