Sulfates are super cheap and it ain't about the sulfur it's about getting it to the plant right away.
Micro sulfates added with sugar (like AEA products, but they use molasses) works just fine. I use brown sugar. (I need to put in a small area of sugar cane so I can just press the juice from it. Cane juice works much better.)
Manganese sulfate is really the most efficient form to use. Please read the following. This is why frequent root drenches work so well. If you acidify that drench with just a tad of citric acid, that would help even more.
Here is the editor of the Farm Journal discussing the best manganese forms to use.... (manganese sulfate).
http://www.agweb.com/mobile/article/how-to-fix-manganese-problems-naa-darrell-smith/
I frequently add Mn Sulfate to the Albion or Baicor chelate and thereby delivering more Mn to the soil in a form that is easier form to pick up. In alkaline soils above a pH of 7, Mn applications twice weekly at the root zone do wonders. At my pH's of 7.2 or so, this guarantees Mn to my trees constantly.