There's a time and place for stuff such as alignment protractors, scales etc.
Scales are useful, but only if the arm has some way to adjust the tracking force. The Goodmans and its ilk don't, so all you're able to do is check that the stylus is tracking somewhere around the 3.5 - 4.5gms it's designed to do.
A Pro-Ject tonearm can be adjusted, but the counterbalance markings are fairly accurate anyway,but for peace-of-mind and just for dicking about with a new toy it's fun to measure.
Alignment protractors... Good tool, but not all cartridges have nice rectangular sides which make any adjustment simpler. Also, how level the tonearm is can be important, but again, only if the arm's pivot post has the ability to be raise or lowered. Not all arms have this.
Measuring the resistance.... Here be dragons.
A phono preamp has impedance not just resistance. That's a combination of resistance, capacitance and inductance. No one messes around with this stuff for Moving Magnet cartridges. Once someone gets in to moving coil carts' then it starts to become more of a thing, but you're not going to put a £300+ MC cartridge on the end of a tonearm of a £200 turntable.Nor are you going to find a turntable with a built-in phono pre-amp with any kind of adjustment.
If you want to buy accessories start with a good carbon fibre record brush.