I have tomato seedlings again. I sowed many seeds on smallish pots, about ten per pot. I used cling foil to keep the growing contitions humid and light.
The cling foil was actually placed on top of the pots much nicer at first but then the seedling grew so long that they hit the cling foil and started to bend under it.
First I thought of making a tent out of grill sticks and cling foil. But found out a much quicker and easier solution. I just placed jars upside down on top of the pots. Looks odd, but works perfect and gives the seedlings longer time to grow before replanting.