I don't see why that couldn't work indeed. I had those measurements saved in my phone but I seem to have deleted them again.

Anyway, on the RockAuto.com site you can read the specs of the bearings used in '71 and '73 and calculate the required sleeve-specs needed. Very handy of them (assuming the specs are correct).

These are the bearing-specs I just found on Rockauto.com:


1971
BCA/NATIONAL Part # A2 More Info {Cone Length=0.475" Bore=0.75" Outer Diameter=1.781" Width=0.61 StoundOut=0.135" Cup Length=0.475" Cone Radius=1.046"}
Taper Bearing Set; Front Wheel; Outer

BCA/NATIONAL Part # A6 More Info {Cone Length=0.465" Bore=1.25" Outer Diameter=2.328" Width=0.625 StoundOut=0.16" Cup Length=0.465"}
Taper Bearing Set; Front Wheel; Inner
======================================

1973
BCA/NATIONAL Part # A16 More Info {Cone Length=0.475" Bore=0.8611" Outer Diameter=1.81" Width=0.61 StoundOut=0.135" Cup Length=0.475" Cone Radius=1.05"}
Taper Bearing Set; Front Wheel; Outer

BCA/NATIONAL Part # A17 More Info {Cone Length=0.47" Bore=1.3772" Outer Diameter=2.3622" Width=0.625 StoundOut=0.155" Cup Length=0.47" Cone Radius=1.203"}
Taper Bearing Set; Front Wheel; Inner
======================================

A quick math gives these specs for the sleeves;

1973 - 1971 = Sleeve thickness
Inner bearing: 1.3772" - 1.25" = 0.1272"
Outer bearing: 0.8611" - 0.75" = 0.1111"

Ofcourse you need to play with these numbers a bit if you want a press-fit on the spindles.
And most of all, double check EVERYTHING and also question and recheck everything I've typed here. An error is easily made ofcourse.

I also recall I had made a small ridge with a radius on the larger inner sleeve, to prevent it from moving out from under the bearing-race towards the center of the rotor hub. This would be a bad thing to happen ofcourse.