Thanks!
The Black Hack is kind of its own thing. The general principles of how monsters work are probably directly compatible with Glaive, though PCs tend to be hardier, so i might bump the damage a bit. 3 points, or 1d6 in the example you give
Monster Overhaul is a great book! And yes, directly compatible
I tend to use monsters out of Old School Essentials. There is a big tome, but you can also buy separate digest sized books. The Monster Book is very portable.