I bought 5 of those seconds easyfits too and I find they leak also. I've only been using cloth for a couple of months so fairly new, but my baby has just turned 1 and is big for her age, so I have them totally un-poppered, the biggest rise I guess. I'm lucky to get 1.5hrs even with the booster. I could try a smaller rise, but I feel that would just mean she's wearing hipsters. I have just put one on her before putting her down, with the little booster folded over to see if that helps, otherwise she's soaking after her nap.
I don't have a tumble dryer, but could borrow one if you thought just one tumble would fix them?
Let me know what you think