oskar,
The procedures any of us use to produce cases does depend on the equipment, experience, donor cases, and money we have at hand. Lacking equipment, donor cases, and experience, the easiest way usually is to just buy the cases or something much easier to form into the desired case. At almost 3/4 of a century in age, I have sufficient equipment and a little experience, but lack money. Others have sufficient money, but lack equipment and/or experience. When I suggest some method of making cases, it is with the admission and complete understanding that someone else may have another way that suits them better. Sometimes I forget others don't have the machines I have or the inclination to acquire and learn to use them. For these people, it is perfectly satisfactory to just buy what they want. It is all a personal opinion, and mine is no better than anyone else's. I believe a lathe( and mill) is a requirement of life.
Mike