From my experimenting yesterday, this seems to be the quickest way to get the three engines in one go with one engineer.
-Jump to one turning and hit it.
-Go AFK and immediately return (Yes, it's a bit cheap. But it's also quick.)
-Go hit the main engine from underneath.
-Jump down to the other turning and hit it.
-If you're doing multiple cycles, go AFK again and repeat the process.
Good for one cycle? Yes. Good for moonshine or kerosene? Meh.