generally, in spermatogenesis  sperms have produced  as a  wave. so the pictures will be different among suctions. that,  why we need to study many sections . you need to  take a mean of the wall of seminiferous tubules and  lumen's diameters. this should be at least for 10 suctions. 

Thank Amal.

Does it means that spermatogenesis is synchronized in the same seminiferous tubule but not always in different seminiferous tubules of the same testis?

unfortunately, i am not sure about that but we can find many waves at the same time in each seminiferous tubules. i suggest this link to you to understand what waves here mean.

http://www.embryology.ch/anglais/cgametogen/spermato04.html

and its worthy to know if this animal was mature or in around puberty