Latex molds have a life of 4 - 6 years. They should be kept away from heat and ultra-violet light in a clean, dry place. I cover my molds with cotton cloth and store them in a climate controlled environment. Latex should be used in a well ventilated room. The strong odor is ammonia used a the preservative for the material.
All latex has a tendency to shrink.
Some vendors advertise minimal shrinkage but it is suggested that you make your model 2 per cent larger to compensate for shrinkage. Mold Design Sections required for the specific form are planned prior to the application of the latex. The flexible latex mold allows complex undercut forms to be made in fewer sections since the mold can be bent and peeled away during use. I recommend two excellent mold-making texts to gain a general knowledge of mold design. Both books have excellent illustration which illustrate the process of designing a traditional plaster mold.