The tolereance on the gauge line for both NMTB type spindles tapers and toolholder tapers appears to be + or - 0.015" on each. So there are a number of potential problems with blue printing.
1) You would have to blue print every toolholder as well as the spindle.
2) If you were unlucky your standard spindle and tool holders would require material to be added in order to blue print.
3) The tool holder flange face would require precision grinding.
4) I think the precision necessary to ensure the 7/24 taper and the flange "come up" together may be tight in the extreme.
I would suggest that if you plan to use the flange of an 7/24 NMTB taper as a part of the location system that you dig out the tolerance specs for something like the HSK system and evaluate if you are able to duplicate or do better on a NMTB taper. I think the 1:10 taper of the HSK system may be the key to achieving the tolerances necessary for dual contact.
This link makes some very interesting initial reading.
http://www.mmsonline.com/articles/100105.html
Regards
Phil