QTR-Quadtone RIP

I'm trying to figure out QTR, getting ready to print target.
eye-one-readme.pdf says:

The 21x4 target is recommended for the best accuracy.  It has 4 patches for each step value and the QTR software will automatically average the 4 measurements which gives a more accurate result.

My question is: what will be more accurate with this target - measurements or printer profile? I understand that every patch measured 4 times and averaged gives more accurate measurement but will  profile be better than with 51-step target?

And for that matter - is 51-steps enough for quality printer profile? Bob Atkins for example uses 4096-step target for RGB profile.


Thank you,
Jacob
http://www.photo3dart.com