I do not think it is detailed enough Matty. We have a much more comprehensive guide for out pups. There are some extracts here
http://custardhamstery.piczo.com/?g=23010816&cr=3
We provide a full pedigree, plus we usually get the cage from the new owner before the pups leave and settle them in. This minimises stress when they move to the new owner.
I think the cage size you have given is way to small. particularly for more than one hamster.
You should stress that Chinese are not really very sociable and frequently need separated so buyers of pairs should be very aware of this. With regard to diet, any new food should be introduced by gradual addition to the old diet to make a slow change so the system can adapt. Suggest types of suitable fresh food and protein and what NOT to give.
I would not mention breeding at all except to discourage people from breeding without research and experience.
Always give your details and offer help and advice throughout the life of the animal. As a responsible breeder no animal bred by you should ever have to go into rescue so we state that should the new owner ever be unable to keep or care for a hamster we have bred that the hamster will be returned to us.
I hope this helps.