I'm in the process of standardizing dice across the game. d8s are for guys who are experts at whatever they're doing.
Later on I'm introducing the Commando unit whose Field Training Specialty means he can use some of the same abilities as Mediks and Mechaniks and Scouts - except he uses a d6 instead of a d8. He's not an expert, he just has enough basic training to do a regular half-assed job.
In theory, a unit completely untrained in these fields could roll on the same tables, but with a d4. Still testing that though. It means I have to redesign everything so that a 1d4 can only get lousy results, a 1d8 gets decent results, and a 1d6 gets half-assed results. The Ker-Triage! Table is pretty balanced in this regard, but the Mechaniks' and Scouts' abilities would have to be rejiggered.