Rocker shaft hold downs

Has anyone else had to machine anything to run the hughes hold downs? Or is he talking about the spacers that go under the rocker shafts to space them up? I do not need any thing to move them up as the geometry is good where they are. I am sort of wondering if I need these over the factory hold downs while runnig solid cam and factory type adjustable roackers? Also looking to help with the rocker alinment over the top of the valve tip.Tyanks to all who have replied and keep the info flowing!
Matt