Torque # For Iron Rocker Lock Nuts?

just did a road trip plus 1/8 mile fun drags. Had one adjuster shear off under the lock nut. Fortunately the nut/top of adjuster was sitting in the head!

Machine shop had told me I needed 30 ft/lbs on the ARP lock nuts. I didn’t go that high, but what would recommend??

And who makes the best adjusters??