You always want to ultrasonic first. I would buy a larger capacity ultrasonic as well, the harbor freight ones are very small. My 10L fit most parts. For a little over $100 you can get a 2x-3x capacity one and itll look cooler and more industrial than the HF one. I threw in entire coin door mechs, circuit boards, even my Indiana Jones gun shooter, that wouldnt have fit in a 2.5L tank.

I think the only real benefit of ultrasonic is the time cut for cleaning. Your way works too, its the degreaser itself doing nearly all the work anyways. Its nice being able to clean parts on the fly in just a couple minutes with these machines, pull them out then reinstall quickly unless needing tumbled. Takes longer just letting them sit in a bucket.