IMO you (or anybody starting) should start with a base and go from there. Last August when I started I had grandiose expectations that weren’t realistic. I currently have a fully functioning PO (person/object) 0 to 9999 and semi-complete PAO to 99,999 (I only have ten separate actions, for me it’s a pain to try to visualize 100 separate and distinct actions) and it works well.
If you’re looking for a simpler, but still impressive to the unexpecting, card sequencing/digit memorizing routine this might be good to start.
The 52 card colours equal 18 digits and could be realistically memorized in a minute or two. The numbers in the link above would be…
660577160134746002
Jim