If anyone is interested in the real engineering design guidelines for needle bearings you can find it here:
http://www.ntnamericas.com/en/website/do...13-e_lowres.pdfWhat you'll find is that needle bearings work just fine for oscillating shafts as long as the angle of oscillation is greater than the distance between the bearings. If you look at a Jesel rocker arm you'll see that they are properly engineered. Some of the super cheap Chinese crap rocker arms use large diameter needle bearings and if you use them with low lift cams you might have a lubrication problem. There shouldn't be a problem with any of the high quality vendors such as T&D or Jesel.
