However, I couldn't find a conclusion. In my case, my data extends to 1.4 A with the R/R free being around 23/26 %. There is also pseudo symmetry, so there are 16 NCS copies in a lower symmetry group than what Xtriage suggested. The map looks fine with density for some H atoms even being visible.
On what basis should I decide whether to use (or not) thin shell assignment? And what is the cut-off for number of NCS copies?