That method is as good as any. There are several ways to position the camshaft to adjust the valves. Stick to one and learn it Print on some card stock and hang under the hood where you can see it while you work.
To make it easier to turn the engine by hand, remove the spark plugs. Put the tranny in neutral. Tighten the fan belt and you can turn the engine with the fan blade. Don't forget to loosen the belt when finished, too tight and the water pump bushing will wear.
On your valve cover. It is sheet metal. Straighten the edges with a hammer and dolly technique. I put a board in the vise for my dolly.
