120 is a decent result but it's what you'd describe as thin hair, think east asian people.
The density on the mouse was 129 hairs/cm², and the stem cells were most probably of a Japanese individual (East Asians sport lower hair densities on average.).
Okay so to put these in perspective for everyone I found some pictures from a wig manufacturer.
"Our factory uses the number of individual hair stands per square centimeter, ranging from 30 hairs per square cm to 150 hairs per square cm. 30 hairs per square cm would be considered an extremely thin, light density and 150 hairs per square cm would be considered an extremely thick, heavy density."
No the intervals are a little bit off, but basically that means that the first wig is
30 hairs per cm squared, while the last wig is
150 hairs per cm squared. The half way point is 90 hairs per cm squared, so should be the medium one, which is what they recommend for young men, although apparently the medium light wig is the most common.
Anyway 129 hairs is basically in the range where the wig supplier say it gets too thick for everyday wear.
The only issue is the supplier hasn't said what type of hair is in the pictures. It probably isn't European hair, and apparently Chinese hair doesn't curl, but apparently Indian hair is quite similar to European hair.
"The texture is very smooth and soft. Genetically, Indian hair is very similar to Caucasian hair in its basic structure."
So yeah, it seems like Tsuji's method is likely adequate enough to give people back their natural density
Sources:
https://www.lordhair.com/custom-options/hair-density.html
https://www.lordhair.com/custom-options/hair-type.html