I have had pretty good results with Black Magic down here. They seem to hit it pretty well. I quit using it when it went up to 8 bucks a bag and I started mixing my own mineral from stuff you can get at any feed store.
Black Magic is rele nothin but salt with some sweet smell added to attract them for a longer distance.
I mix trace mineral salt and dicalcium phosphate together and add some powdered grape Kool-aid to just add that smell good factor. I have great results with this mix