Back at the beginning of this dialogue the question was asked what was wrong with Boardman feeders.
Nothing, I use them a lot but they must be used properly to prevent robbing.
Use of the Boardman is easily done with 2 feeders per hive with the entrance located between the feeders, arrange feeders and any needed reducer slats so that there is less than 2 inches of entrance space on an 8 or 10 frame hive. For a 5 frame nuc no further entrance reduction is necessary other than the 2 feeders.
If only one feeder is being used be sure to use some type of entrance reducer so that the feeder is placed next to the edge of the entrance and use some type of reduce configuration so that less than 2 inches of actual entrance area is available to the bees.
For a single Boardman feeder, where F is the feeder, x is the reducer, and E is the entrance the configuration should look like this: FXEX
For a double Boardman feed it can look like this: FXEXF or in the case of a nuc: FEF
These options places access as far as possible from any robber bees and allows the home bees to best defend their hive.