Every time I try to use cloth for overnight for my 6 month old son, he gets a yeast infection rash. I use prefolds with snappies, bummies whisper wraps, and a stay-dry doubler made of fleece and terry cloth at night. I always end up putting him back in disposables at night because after about 2 nights, he ends up with a bad rash. What is a good overnight system?
There are two things that come to mind when I read your question. First, that the rash only happens at night tells me that it is possibly not yeast. Yeast would be living in the diapers all the time and would not go away so easily if you continue to use cloth during the day. In my experince, yeast sticks around day and night! Second, it is possible that your son is sensitive to the fleece, the detergent you use or both. You don't say what detergent you use but sometimes children have been know to have skin issues with optical brighteners and enzymes when left on overnight since the Uric acid in your sweet boy's urine builds up from a long night of sleeping. Check your detergent, even most "free" types still contain one or both of these add-ins.
Before I would ditch the prefolds for night, I would try a couple things first. First, strip your diapers, including your doublers really well (rinse in your washer on super-hot water several times). If he still gets the rash, then try leaving the fleece and terry doubler out. If he still gets the rash at night, it might be time to pick up some pocket-type diapers. They are consistent at night and easy to accommodate a variety of wetters!