Thanks for your replies. Because time was of the essence (when isn't it for cake decorators
), I went ahead and tried the piping gel and boy does it stick!!! (I brushed it on with a wide pastry brush).
I was afraid to use water because I thought it might start dissolving the fondant slightly before I was done pulling it away from the cake as I smoothed it, maybe causing it to tear.
NEXT time, I'll try using BC on one and shortening on the other since I happen to have (4) 6" cake dummies