if it comes to serfs it depends on the chapter its hard to generalise. I can bet that Iron Hands for example love theirs.
if comes to automation level on Astartes ships 60k crew mean that ship is very automated, by RT Lunar class Cruiser need 95k crew and its only small 5km spaceship. Battle barges are by size compared to true battleships, witch may have crew of around 180-250k.
On number of Serfs and Dark Angels chapter...
insane 5 Battle Barges, 10 strike crusiers, 8 rapid strike vessels and ofc THE Rock. that chapter have probably biggest number of serfs amongst other chapters.