It's been about a year and a half since I (mostly) finalized my images from 000 to 999. I'm using Major system and have put them into a memory palace of my choice (Demon's Souls world areas). I've also been using Anki to reinforce them and focus on the most problematic images.
As fun as this has been the recall times are fairly long and some images just don't want to stick no matter how often they come up on my daily Anki sessions. Compared to my 2-digit PAO images the 3-digit ones feel much slower and more awkward in use.
I've been contemplating on ditching this experiment and honing more on the PAO, but I still feel there's some potential here despite the difficulties. Any tips or experiences on getting the 3-digit system to a more usable level?
Just an observation: partly this frustration is caused by how Anki (or most spaced repetition tools) works by default. That is, the difficult images come up most often. This easily creates an illusion of never learn to remember these. So since in reality most of the image recalls range from easy to somewhat challenging, I guess I should focus on improving those more difficult images instead of falling into that illusion of defeat.
Still, even if this system never becomes as fast and as practical as my PAO, there's definitely a fun challenge in it, and the idea that any three-digit number out there has an image relating to it in my head. And maybe some day (I still got years, maybe even decades ahead of me) they become so ingrained that the recall process becomes automatic any time I see such a number sequence.