Any valve lash advice from the gurus?

If your idles down at like 600, thats 300 per minute valve cycle so 5 bumps per second on each adjuster. Use a socket and a 1/4 drive and good call on the bent feeler guages. I'd get it hot and shut it down, adjust all the rockers and then start back up and check while running. I bet 90% will still be spot on. I would adjust closed valve while opposite is wide open.