first get wth a local guy that knows how to feed holsteins,we use smidely steer stuffers,kinda spendy for new ones,i used to build them.i have seen the hog feeder up on blocks looks like it works,we think we get better conversion with cracked corn,have to pay attention so you don't run into acidosis issues,we run some soyhull pellets or oat screenings to bulk the ration up,or oats,whatever is cheaper.right now we are running,300 lbs  ddgs,200 lbs soyhull pellets,100lbs balancer,and the rest corn per ton.have in the past used reject cereal product,koolaid mix,etc.anything dry it will work in a self feeder as long as it is balanced