I can not memorize. Though I have to say my memory is improving since I have started daily gratitude and acceptance.
At first I thought I would have to tattoo the symbols on my arms. But I am a very girly girl and that would never do.
Then I purchased Reiki decor. Pictures that look like decor but I could look up and see the symbols.
Then I realized that the symbols are implanted in my aura and that is enough.
Then I started studying reconective healing, did gratitude and acceptance and wa la...I am conected, on and ready to go.
So...I may be wrong but I'm not sure the symbols are nessasary once you learn to connect?
BUT...of course it's a different story if you are giving attunements. So if I was giving attunements, I'd have to use decor.
Of course you don't need the symbols to give reiki. The symbols impart different qualities to the energy - which you can do with intention I suppose. But for me the symbols are part of my intention. Drawing CKR is a key part of my intention to give reiki. But the symbols ARE a key part of Usui's legacy.