I don't think you should let the temperature go below 70! From my experience peat with a lid gets you seedlings way faster than the paper towel method (which has been my main method for years). I've just switched to peat and lid. The early jalapenos only took 4 days to become seedlings. Then the white and red habaneros only took about 5 days. All of the red habs, white habs, and early jalapenos became seedlings. 6 days for devil's tongue, bih jolokia, and some more. My Bhut jolokias and Trinidad Scorpions are going to pop today on day 7. I kept the temperature between 80-85 the best I could (sometimes It'd get in the high 80s and I'd have to cool it off). I have extra seeds in paper towels and ziplock bags, but they don't grow half as fast. I still have not gotten a seedling out of them (should get one tomorrow that was planted). Edit: I had the "greenhouse" with peat in indirect sunlight for passive solar heat because I don't have any heat mats. I'm very suprised. I was expecting to start seeing seedlings in a week and even more time for the bhut jolokias and Trinidad scorpion Butch Ts. PS: A cover on those trays will bump the heat up. You could also try to move them in indirect sunlight with the cover if it's still not hot enough. I'm not sure why some of your peppers turned yellow and died! My little seedlings became very healthy with the lid on. I have the lid off now because I don't want their cells being so wet and the humidity being very high. Maybe there was too much water in their cells.