m0useanswered grow question 3 years ago your growing a photoperiod fast version. meaning its half auto flower and half photoperiod.
I'd transplant them in week 3. Into their final pot and veg them out for another 4 weeks.
If your cupboards is that small you may want to get a different setup, you can just hang the lights over them in the room it does not have to be sealed. worry about that in flower. 75cm is about 2.4 feet. that's not a lot of room to work with vertically. The light alone will take up 9" or more.
If you can find an big ass cardboard box that would be a better option. I made my first grow tent out of Styrofoam and pant. it worked out for my first two little grows. but then I got a bigger tent when I knew what I was doing.
Good Luck and Happy Growing.