Holster selection will depend upon your intended uses (field, range, concealment), your physique, and perhaps your usual wardrobe as well.
Your S&W 624 is made on the N-frame (also called the large frame, although S&W now makes larger models). It will fit in any holster made for the N-frame provided that the barrel channel is compatible with your handgun (original style underlug, full-lug, etc).
Beyond that, I would suggest that you use a sturdy belt in a width that matches the belt attachment points of the holster. This will improve comfort, concealment, and security considerably.
Every holster design involves compromises between four basic factors: comfort, accessibility, security (weapon retention), and concealability. It is up to the user to determine which factors are most important for his uses, and how much of the other factors he is willing to compromise.
Best regards.