If you take a close look at Taylor's beautiful rifle, you'll notice that the comb line is almost parallel to the line of the bore. There's a reason modern center fire rifles look that way as well. I think sometimes we have a tendency to over emphasise drop at comb and heel and cast off, etc... I agree, this becomes more important if you're only shooting the rifle offhand, in the same position each and every time. But, as soon as you alter the position from which the piece is fired, all those measurements change. That's why all the modern, competitive shooters have stocks that adjust for comb height, LOP, etc. I'd be willing to bet that the architecture of the rifles you mentioned would support a heavier caliber well, and not lock you into concrete measurements, per say. Just my thoughts...
Ed