OK, after rereading your post and especially #26 above, I think that I finally understand what you mean: at such long range where the scope must use the maximum x25 magnification to be able to see a man size target, only part of the reticle will be visable due to the smaller field of view at this power (that is, about 8mil below the center crossshairs
It didn't occur to me become I am not experienced with variable power scopes, only the set 4x ACOG.
Still, at least according to my calculations, it should be possible to use this scope--even without a canted base--to provide enough verticle lines for holdover, as long as the rifle is zeroed to 2000m
According to the charts, to hit a target at 2475m with a 2000m zero you will only need to to come up about 13mil. To have 13mil of verticle stadia lines viewable at x25 magnification, you could use the top of the reticle-- PointA in the picture below, to zero and use Point B for the holdover on the taliban target (which will only be about 0.7mil high at this range
!)
To zero the scope for 2000m, you would use top line A to aim at a target pasted on a large background and and adjust it so that the POI is 585cm above the POA on a target 300m away, or 203.5cm above a target that is 100m away (see the short range trajectory with 2000m zero in table below
I am sure that there is a more practical way of doing this, like was already suggested with a canted base
However in any case, I think that it makes more sense to zero 338 or 50 cal sniper rifles used for very long range mission at ranges longer than 100m or 250m
From some of the posts I linked above, there is indication that this is actually done in the field