I noticed my seedling was overwatered and leaves after cotyledons were sagging so I let the soil dry and put a humidity dome on it. It’s bounced back and has the proper turgor pressure. I was told before to leave on until leaves touch inside of solo cup but is that just misting the inside and no water added to the soil??
Correct until the dome is removed. Seedlings only need a few ml of water per day. It’s important to let the soil dry out between waterings.
Do you recommend until the leaves touch the outside of the cup as well? Then do I water around it as if the cup was still there or give right to base of plant
Correct.
Watering around the base is a good idea for plants that already have developing a root system. All a seedling has is a sole tap root. What I do is water directly at the base of the plant for 2ish weeks (around the time of the first transplant) then begin watering around the plant to encourage the roots to explore for water.