I too remember that discussion because I was a subscriber to Phil Summers' Patreon for about a year during which he released six issues of his Hand-Drawn Gaming series before closing his page down: Castlevania, Gimmick!, Double Dragon 2, Mega Man, Teenage Mutant Ninja Turtles and Bionic Commando.
The artwork was as good as the free guides but they were smaller at eight pages each and usually only featured partial maps or simple tips. I can't complain because the artwork was very good, reminding me a bit of Katsuya Terada's artwork for Nintendo Power's three parts Secret of Mana guide in issues 62, 63 and 64 way back in 1994.
If he's working on an actual book, I'm curious to see what it's going to be about!