Glad to hear you're still putting in the hours. I was impressed with playing on You Drank Some Darkness, so I can only imagine how much you're building upon that now. Sweet guitar too!
I haven't seen that book. I have played and enjoy playing live, but not much recently. I do dedicate a reasonably amount of time playing instruments though, so it can certainly still be relevant in that way. I read some of the preview about practising slowly and it seems really interesting. I'll add it to the list.
I can relate to the endless pursuit to get the perfect take when recording. It can make you go kind of crazy. But you're on the right track in letting go of that perfectionism when playing live. Partly because, as you say, some people won't even be paying close enough attention to notice. But more the fact that any minor mistakes and fluffs- that in a recording would be immortalised and forever noticeable- exist for a second or less when you're playing live. If you nail the show overall, people won't remember that you didn't fret a note correctly or messed up a fingerpicking pattern.
I look forward to hearing your future output!