Male dogs are relatively easy to take care of in this sense. The surgery is a lot less invasive. I'd recommend our vet in Qizhang, Xindian, who can take the balls off a cat in less than a minute... both of them (which means less anesthetic).
It is often advisable that doggie in question has been vaccinated beforehand and is in good health. A complete checkup before surgery is advisable. That said, dog must not eat at least 8 hours prior to surgery, nor water be given, to avoid vomiting/choking.
After the surgery, dog must be kept in a warm, quiet place for at least a day or two. Please rest assured that dog will not miss his glands. Dogs do not have that concept. He will, though, probably become more quiet and easy going, as he will not have to fight other dogs for supremacy over females. It is a myth he will gain weight. That has to do with age and exercise and feeding, and that is you, the owner's, department.
Cost: about 2K, average. Less or with refund if you live in Taipei City.
Let us know if you have any other questions. Kudos to you by being a responsible owner and "fixing" your friend. he will appreciate that.