I read the Wheel of Times series years ago and never read Spring. When I decided to re-read the series, I began with the prequel New Spring. To my delight, it begins with Moraine as an accepted, learning and training at Tar Valon. She and her best friend, the future Ameylin Seat, are working in the current Ameylin Seat's offices when they over hear a prophesy of the Dragon Reborn, a baby born on the slopes of Dragonmont. Thus begins the search for a baby with the last king of the seven towers at her side. Excellent!
I fun read that sets some of the back story about WoT. Clearly written afterwards. Can be read anytime after the first three books. Really just about Lan and the early years of Moiraine and Siuan.