First 8 seconds are untreated, then the video after the effect was applied. It's quite a difference.
This new plugin from Seed came to my attention from FCP.co today and after asking if it worked with time-lapse video and getting a positive response.. I bought it immediately. De-flicker plugins cost 100s of dollars as a rule, for too much for me to buy just in case I need it. This is only 29$ USA for Final Cut X so it's well worth it.