Balancing a 360 internally/ internal balance

I have had a machinist use the profes

sional products balancer before, the machinist was an older fellow and didn’t seem to know any horror machining .

He couldn’t do more than 3 angle valve job not insert valve seats into a cast iron J head.
The professional products balancer is what he utilized to balance the previous assembly.
I’m not sure what to expect with the new-to-me machinists I’ll find since I have moved.
Post your location, someone might point you to a known good shop.