I made all three wrenches but I have also read about people holding the valve spring retainer in place with a screw drive. My feeling is to do what ever works with out damaging anything. I made the third wrench because it was easy to make and I thought it might help which it did the first time I adjusted the valves. If you do a search for valve wrenches you will find what I made plus what a lot of other people made.
When I turn the engine to adjust the valves I hold the stop lever down and turn the engine with a start button. As long as you hold the stop lever you should not have any problems.

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1983 300SD
200000miles