Timely post, I was just checking out my new HF stainless steel calipers and ran the figures from my calculations through DT Swiss's wheel calculator. The first time yielded 290/292 (spoke lengths) for left and right sides up front. (32 hole, 6-bolt, 3X pattern) The second time, I did all the calculations anew and came up with 290/291. That's pretty close if you were choosing from spokes sized in even sizes.

So, yeah, I agree the measurements can be a bit forgiving.