First off, the OP going in and
changing things after the mechanic worked on the car, and taken it back is a surefire way to get under the mechanic's skin__HOW can he warranty any work, if the car owner takes it home and redoes things?
Secondly, if the OP IS CAPABLE of understanding and making said changes, WHY take it to the mechanic?
Those are just some personal observations, and as we all know, opinions can be worth nothing. No offense intended, of course!
It was said to me long, long ago by a mechanic who'd earned his stripes, that "loose valves won't cost you money, tight ones will!" So just because you can hear them, it doesn't mean that you shouldn't. The intake valve lash matters less, as it it always getting a cold blast of air and fuel every time it opens, but the exhaust valve lives a much harder life, and the only chance it gets to dissipate heat is during its brief contact with the seat. The tighter the lash, the shorter the contact dwell.
The oil in the rear carb would've been enough to convince me, but to see the rocker-arm oil outlets peen'd over seems conclusive; work rockershaft and bushes! Those outlet holes serve a purpose too: that tricke of oil lubes the rocker tip/valve stem contact points, so closing it off completely accelerates wear there.
For an in service update on Rocker Arm Rebuilder's work, you might ask Jim, aka healeyblue, as they were used when rebuilding the engine that he looks after.
Obligatory pictures...