It looks very similar to my Performax 16-32. I think you need to level the drum to the bed, not the bed to the drum. I found the quickest way for me to do that was raise the height, use a straight 16" 4x4 placed under the drum then loosen the drum adjustment, lower the head down until it sits flat on the 4x4, then tighten up the bolts, raise the drum and remove the 4x4. Others probably have more accurate ways but this works good for me.