i would say production shopits almost a must to keep quality control and speed up. in a nome or small shop i supose its more personal prefereance. HAWK had a small shop and had the PII and i think upgraded from that to the PIII. could be a prefectionest type personality causted it or he just valued a nicely ground tungsten. , i supose that dosent help much dose it. i think if i was going to use thorated a PIII would be a must for dust colection in my thinking but then i dont see the point to useing it anyway when there are better options available that are not RA. i supose ther could still be some contracts that will speck out the tungsten to be used and thorated could well be in there.
for a small not so buisy shop i think a sharpie would be fine, with $30 dubble sided replacement cutting wheels its a fairly cheap to maintain option that will get you repeatable results for your tungsten grinding needs. at the same time many argue none are needed just throw it on a bench grinder and get it close and you are good to go.
tuff call realy, personal preferance has to play a large role in this desition.