I also use the slow set epoxy, preferably the marine version, for installing inserts and for bonding inserts to broadheads. The marine epoxy usually blends to a gray mixture when the two parts are combined and is very strong, somewhat flexible, water resistant, etc. JB Weld epoxy is very similar. The fast set epoxy is good for most purposes, but the slow set is much better. Barge Cement is great stuff, but not for inserts. Duco has limited use, mainly for feathers on wood shafts and for other fairly light adhesive purposes.
Allan