The stance for the serve
Players use two types of stance to serve with that allow them to transfer weight. The first is called a pin-point stance and the second is called a platform stance. The pin-point stance is when the back foot is moved forward adjacent or next to the front foot for support. This presents the server with a base that allows him to push off with both feet when transferring weight.
The platform stance is different in that the back foot is not positioned forward near the front foot and the majority of the force is produced with the front foot. The platform position is like the Quarterback in the football game that is ready to pass; he lines up to his target and sets his feet then releases his weight from back to front.
The pin-point stance is like the basketball player who is going to take a jump shot; he lines up with both feet to the target then pushes off the ground with both feet. The key in both stances is the weight transfer or ground reaction force. This is how well balanced in the timing of hip rotation and forward momentum is used to transfer weight from the ground up.
The strongest servers seem to have a pin-point stance, because of the additional foot to push off the ground with when serving. The reason is the matches that go 5 sets or a long 3, in the platform position the front leg produces all the upward force. The front leg tends to weaken in strength producing more weak servers or double faults. The position of pin-point provides two legs to generate power that distributes the strength requirements equally throughout the match. The choice or preference that you use is important for weight transfer, consistency, accuracy, and power. The method should have these characteristics to be the best server at your club. Try them both for fun and see which one works best for you.