One thing you should do that isnt often mentioned on these collimation tutorial pages is to accurately centre your spider in the tube. Dont assume that it will come correctly fixed from the factory, mine wasnt
You should only need to do this once. If its off to one side you can mess around for ages wondering whats wrong when the crosshairs never line up with their reflections.
After you have done that align the secondary to the focuser tube and then adjust tilt so you can see the reflection of the primary and its mirror clips centred under the focuser. Yes this is the fiddly part for sure.
Third step of course is to adjust the primary centre spot to line up with the
cheshire illuminated ring, not the crosshair.
If and
only if the secondary is aligned correctly will the crosshair reflections stack on top of each other in the centre of the reflected centre spot as viewed in the cheshire. If its out a bit it means that your optical axis isnt aligned to the focuser axis, giving a slightly tilted focal plane.