I've tried all types of bucket and barrel feeders. Dead bees is almost a given. One of the neat things I tried was buying old used tennis balls and filling the top of nbarrels with them. Enough to float them on the entire surface of the syrup. Worked pretty well. The balls soaked up the syrup and the felt of the balls allowed plenty of places for the bees to walk, groom, etc. But I still had dead bees.
The best feeder I have now, are two small hog (or maybe chicken) trough feeders. One is 6 foot and the other 8 foot long. They are about 6 inches high on the sides. I fill them up, and have wood stripping that acts as floats. The edges of the trough, and the floats, allow a maximum amount of space for bees to land, walk, feed, groom, etc. Hardly ever dead bees.
I think, based on my own experiences, that perhaps another type feeder would be best. Buckets, with high walls, slick sufaces, and bees trampling over each other, just makes a potentially bad situation for bees to have to deal with.