FWIW, my Sanglas bike -yamaha xs400 engine- has a similar oil filter setup than the CB750. The Yamaha engine, being 10 years younger, has some cool things like showing the torque for the oil bolt on the oil filter housing.
Can't remember now how much it was, but just let me tell you that my torque wrench -the big one- had a higher torque even in the lowest setting. I had to use the small one -1/2 fitting- to torque the oil bolt. I could have never imagined how little it was. Something like when it is starting to tighten, then "click". If you use a regular spanner, you have to stop tightening real quick. ¿Have you heard about spark plugs tightening by hand and then just 1/4 turn more? This is even less.
So, for next time on my CB750, I will use the same rule. I didn't tighten it much, but definitely more than the XS400 specs.