Valve lash adjustment isn't very hard at all on a 24V, all you have to do is line the mark on the pump gear at 12 o'clock then 6 o'clock to adjust all of them. Just gotta know which 6 to do at 12 and the rest at 6.
As far as a good diesel shop in St. Louis, look no further than McClain diesel service. Last I knew he was down around Fenton.