Perhaps a photo essay will help on the differences. All non-tilt column shafts have the same spline size, 1969 to 1973, so no problem fitting there. As for the steering wheel base, ‘69 - ‘70 are close, ’69 is smaller by 1/2 an inch
69 on the left, 70 on the right
1970
1969
69 column and wheel fit.
Here is the 1970 mated with the 69 column, as you can see it is wider than the column.
The horn ring would hide the differences for the most part.
Here is the wheel from a ‘73, very similar to the ‘71. Note that the horn mechanism is quite different than the ‘69-70, it will look odd, but functionally would mount without a problem.
Hope that helps.