Im keeping them on this rack in front of my Bay Window which gets great mostly partial & indirect Sunlight . The smaller plants in trays I return to indoor greenhouse with the LED grow light at night because the window,area can be a bit chilly even with baseboard heat below.
I did thin a few of these out more....keeping it at 1-2 plants per cup for now. So I suppose with nearly 800-900 seedlings which are at different stages of growth I should expect a percentage of the plants to be duds or sickly....