If you were to do a relative compression test and remove no 1 glow plug to identify a cylinder, couldn't you then do a ckp vs cmp using a trigger on the ckp signal.

The reason i ask is i don't understand what difference it makes if the cam is set 180 degrees out as its only the same principle of replacing a timing belt but setting the timing opposite to where it should be if using pins.

Eg,

If the camshaft locking pin was meant to be at 12 o'clock but you set it at 6 o'clcok with the crank still at tdc it is still correct.

but if the camshaft pulley has spun 180 degrees leaving the camshaft correct wouldn't this then show up on a ckp vs cmp capture as the reluctor ring spacing/size would be reversed.

Hope you understand as i'm confused and i typed it out.