There are two unique & separate items to consider with level:
The elevation adjustment, or the crosshair (if the scope even has one).
Both are scope leveling to one plan or the other.
Gun cant itself doesn't matter beyond whatever is comfortable & consistent in use.
So all this leveling of rails, rings & bases is of no value at all..
The main reason to level the action,scope and reticle is to prevent windage changes during
elevation changes.
By leveling the scope reticle to the reciever, the fact that the barrel is pointed upward to the
line of site. no mater how far the shot the bullet will pass through the center line of the bore
and strike above or below the the aim point without having to compensate with the windage
adjustment.
I have seen many match shooters cant there rifles and be very competitive but this was on
fixed distances and they all use windage adjustments to compensate.
Windage is hard enough to correct for without having to use both windage and elevation
for correction of canting.
By keeping everything level, all adjustments can be made much easier for elevation and windage
corrections.
Leveling the reticle with the rifle action is easy and well worth the effort when hunting at
different distances.
Just My opinion.
J E CUSTOM