For ganache, it's all about ratio. You state that what you made was too "goopy" but all you need to do is add more cream or more chocolate to nudge the ratio in the direction you'd like it to go (thinner or thicker). I don't know why you'd put shortening in there though...
If you dip biscotti in ganache, it will not firm up enough to stack, bag, or handle without messing up the finish. All of the biscotti I have ever seen has been dipped in just chocolate. You can use a high quality, "real" chocolate (courverture) but you will have to temper it to get it to set and shine right. You can also use coating chocolate (aka almond bark, candy melts) which is designed to set without tempering, just melt dip, set.
Quote by @%username% on %date%
%body%