Thank you to everyone who has responded.
Here and in DM.
My exact words to the client were
A cylinder hone will fix the groves, it is sourcing the springs that has proven problematic in the past.
That was before coming here. I still need to actually go see the machine in person now that they have it open.
Truth is I don’t feel like honing this myself, and the machinist I use would probably prefer to chuck it rather than use a hone. I could be wrong, and I’ll certainly point out it’s not a high tolerance job at least once.
If a hone is truly the “right” solution, we’ll get there 
I don’t have an automotive machine shop on my list…
I’m also serious when I say I’ve had trouble sourcing springs.
Anyone got the spring plug?!?
Care to share?
Or even how to define the springs you have to the folks who sell them?!?
How about you @Kingofthekush420 you got a source for replacement springs for chinese wipers?