Ah, yes that looks like a good technique for alignment check
If you make a centre mark on the dummy axle
Pull string so it follows steerer centre-line
String should align with mark on dummy axle when forks are right - no measurement required!
fair enough.
The other thing that your dummy axle solution does is give a quick check that you've still got 100mm OLN which is also pretty important when you bend the forks!
Ah, yes that looks like a good technique for alignment check
If you make a centre mark on the dummy axle
Pull string so it follows steerer centre-line
String should align with mark on dummy axle when forks are right - no measurement required!