I always prefer to direct dose my birds so that I know that they each got the correct dose, just my preference. I think the question here is whether your birds are remaining infected after treatment, or are becoming reinfected from the environment, the only way to know for sure is to do a fecal float test before and after, to see if you have gotten rid of them for sure. I worm regularly for roundworms as they are in the environment and my birds will become infected again. Tapeworms require an intermediate host, so they are picked up when the bird eats an insect that has eaten the tapeworm egg, so slightly different mode of picking them up, still possible that if the environmental load is high they can re-infect after treatment. With any parasite the options are limited to TRYING to reduce the load in the environment as much as possible with sanitary practices and field rotation when possible, which is difficult, and treating regularly to keep the load down. I've not dealt personally with tapeworm, just roundworm, but from all my reading the treatment recommendation is usually praziquantel, which both the Equimax paste and the Zimecterin Gold contain. All I can recommend for you is to use a wormer that is effective on tapeworms, and get a fecal done after treatment to see if you have gotten them all. Then if they become infected again you know it's re-infection and you will probably need to do regular wormings to keep them under control due to the environmental load. Hope that helps.
Here are a few links: https://wagwalking.com/bird/condition/tapeworm
http://www.melbournebirdvet.com/parasite-control-in-poultry.aspx
http://www.poultrydvm.com/condition/tapeworms
Here are a few links: https://wagwalking.com/bird/condition/tapeworm
http://www.melbournebirdvet.com/parasite-control-in-poultry.aspx
http://www.poultrydvm.com/condition/tapeworms