“I solemnly swear that I am up to no good.” vs. “053250411391271”
But to be fair, I never end up with nice sentences. It’s more like “Thank you, rainbow. Clock firework” and I imagine myself thanking a rainbow and telling it to “clock firework”, whatever that means…
As to how long, I think it could’ve been a couple of months doing a dozen or so conversions. In total it’s a very small investment of time, assuming you space it out and don’t cram. It really helps to use the Wikipedia mnemonics (like how 4 is kinda like a mirrored R).