OK so this must seem a blur of information, so let me reduce it to this exact scope (in another branding) and how I managed to accurately and more or less permanently collimate it - a process made more difficult by the finicky screws and the "floating" spider.
0) Study the construction of the entire assembly outside of the scope.
1) Remove the secondary completely leaving only the spider vanes and hub.
2) Shove the spider vanes as far rearward as they will go in their slots.
3) Remove the primary cell leaving an empty tube other than the spider vanes and hub. You don't want the reflection in the primary confusing you as you set the position of the secondary.
4) Make absolutely sure the spider hub is centered in the tube. I made a cardboard template I could place over the vanes with an alignment hole in the center. Adjust the length of the spider vanes using the knurled nuts so that the center hole of the spider aligns with the center hole of the template.
5) Put a piece of white paper opposite the focuser.
6) Install the secondary in the spider hub but back out the 3 adjusters so that the secondary flops around on its center post.
7) Holding the secondary assembly with your hand, tug on it toward the rear and manipulate it until you find the place where you can center it in the focuser, by adjusting the center post position. After this, do NOT adjust the center post again.
8) Turn in the 3 adjusters until they hold the secondary fixed.
9) Look at the image of the open rear end of the tube in the secondary. You want to have the end of the focuser tube, the outline of the secondary, and the image of the open end of the tube all concentric.
Doing this, be aware of the degrees of freedom you have. They are the 3 adjusters, and the rotational position of the secondary. The 2 adjusters opposite the focuser should go in the same number of turns very nearly. The final adjustment should be using the 1 adjuster on the focuser side of the hub - this controls the tilt of the secondary.
Once the secondary is properly positioned, replace the primary cell and do not touch the secondary again.
All this need not be done with millimeter precision at f/10. If it looks right, it is right.