I was doing a bit of research yesterday and picked up a pretty damn handy tip I thought I'd share for those that use a meter and calibration software, working with 10 point white balance.
Traditionally when calibrating the greyscale you'd use two point white balance, say at 30% and 80% or whatever to get things in line and then iron things out using the 10 point white balance using an 11 point pattern. Now while this is obviously more time consuming, what you should do is first take a full 21 point pattern reading and look at the mid point readings, 5%, 15%, 25% and so on (I suppose you could also just measure those and work off that at first). Use the two point balance to flatten those points out as best you can and ignore the 10% stimuli. Then go to the 10 point adjustment and iron out the regular 10% intervals, there'll be a bit of back and forth between the 10 point and 2 point to fine tune but it actually works really well in the absence of a 20 point white balance option.
Besides the smoother greyscale, it really helps nail that difficult transition out of black when trying to implement BT. 1886 gamma tracking.