The word “workflow” gets thrown around quite a bit. It’s not one of my favorite words because in practice, it gets treated like a synonym for “recipe.” Unfortunately, there’s no single one correct way to do ANYTHING in photography. That would make it easy.
So instead of saying, “Here’s my Aperture plugin workflow,” I’m going to say “Here’s my Aperture plugin style.”
When I am working on an image, I try to get it as close as I can to perfection within Aperture BEFORE I send it on its round trip to a plugin such as Nik’s Silver Efex Pro or Tiffen’s DFX.
This way, the image lives in a non-destructive environment as long as possible.
Using this approach, I can have the same exact version of the image available to me for use with different plugins. Then I can stack the results and evaluate them side-by-side.
There are rare occasions where I’ll do additional image correction in Aperture after I have round tripped the image to the plugin and back to Aperture. These instances are usually simple color tweaks.
What’s the best approach for you? Experiment and decide for yourself. I’m sharing what works for me. I hope it helps.