Slowly and incrementally increase the sun exposure every two to three weeks. Occasionally wet down the foliage. An alternative to acclimation to sun is acclimating the palm into filtered light, planting it in filtered light and then allowing the plant to slowly grow into the sun. A general rule might be the bigger the better , but pocketbook limitations may apply. I would recommend planting acclimated plants of at least one half meter height.
Larger plants seem to better tolerate the shock associated with transplanting.
Very durable species will most likely survive regardless of the age of the planted palm. It takes a palm about 12 months after planting to start looking good. During its first six months, the plant is establishing new roots and acclimating to your gardens temperature, soil, and humidity levels. Existing leaves may yellow or age. This is also seen with plants taken out of shade structures.