Repotting seedlings

Considerably bigger, we’re they from seed if so how Old ?

Ready for re pot or wait a few more days? Roots are looking lovely at the bottom of my pots and the soils holding together just fine when I checked..

After I put them in 15 l on my first watering Should I water enough for run off or first feed just 50 ml like they was getting in The party cups to get them used to it or do I wait for a cup of run off which would be A few litres?

Also what temperatures and humidity would you reccomend for veg and flower

Also will they be fine to go in my tent under 600w hps if I keep the light as high as possible?

After I finally repot to my 15 L will they be okay to start of with 500ml water and work my way up or should I straight away water till I get run off in my saucers leave them for a bit then empty so I know averagely how much they can hold? Don’t want to kill them by overwatering but also don’t want to underwater

I would wait until the plant is bigger before transplanting it. It probably doesn't have much of a root structure at this point and the medium will fall apart if you attempt to transplant now. Usually around day 14 (depending on growth) is when I do my first transplant. At that point, the plant has a few nodes.