It often depends on the species, some are more tolerant of lower humidity than others. The trick with lowering humidity, and it is a good idea to do with as little humidity as possible, is to GRADUALLY acclimate them to less humid conditions. Too quickly and the dew will evaporate and the leaves will not be attractive. Go slowly, and as new leaves are produced these will be more tolerant of the lower humidity, and should produce good dew. To take a plant that has never known less than 100% humidity and try to grow it with 50-70% is likely to cause some drying of the dew, even if this is the ideal level for the plant. My spatulata grow outside in pretty much full sun without problems, so for this species at least lower humidity is possible, but you must be patient and observant, and remember with lower humdity the pots will dry out much more quickly, so be sure to keep them well watered. If acclimating to sun, morning sun is best for a couple of hours, then bring them back into higher humidity and lower light. Get them out when the day is humid and overcast for longer periods. The advantages are a plant that is tougher over all, better able to resist fungus and other pest attacks, and more likely to flower and set seed. It's a little work at first, but the results are worth the effort. Other factors come into play, a dry wind is to be avoided always, and conditions vary from place to place. Just go slowly, and if the plant objects, go even slower!
