Many great projects are produced from lumber stored in less than optimal conditions. Temperature fluctuations shouldn’t be a major issue. Kiln dried lumber is generally not only dried but is also heated, and that changes the resins in the lumber so that the moisture content (MC) will fluctuate less than it would in air dried lumber. The main thing to remember is to bring it into an area that approximates the MC present in the area where the finished item will “live” before working it into the finished size and shape. One option is to temporarily store the material stickered or on end under your bed or in the closet for a week or so (old timers used to say a year for air dried lumber) prior to using it. You should always follow the practice of selecting stock for each piece of the project to minimize the effect of swelling and shrinking from changes in MC. Coating the ends of raw stock should also help to equalize MC throughout the piece and slow MC changes in the wood. Sticker the stock if possible to try and equalize the MC throughout the stock to minimize warping and checking. Small pieces of stock are less of an issue simply because of the smaller physical changes from MC changes.