sounds right. I do a lot of tomato gardening, and in this part of the world, sometimes I have to cover my plants (outdoors) because of the massive amounts of rain. Yellow leaves is usually one of two things, over watering or under watering... since your saying you think your over, your probably right. Just cut back. The top of the soil doesn't have to be wet, it's the roots that need the water. Try to stick a tooth pick into the soil after ground level goes dry. When you start to get dry at one inch into the soil, it's time to water. That's just my personal opinion from tomato growing, i'm a rookie with bud, but i'd assume that the same theory would work.