23 ounce beer cups with hempy mix...perfect for seedlings the first 3 weeks. https://www.icmag.com/ic/picture.php?albumid=61&pictureid=73060View Image
https://www.icmag.com/ic/picture.php?albumid=61&pictureid=1484447View Image
But you will still have the problem to transplant them (if this is one).
I just transplanted a 2" seedling from soil to Hempy AS A TEST, my what a pain in the ass! This is why I earlier asked around whether folks are putting seedlings into their final containers (in my case just 7L 2gal containers which are fine for now)...
Or said differently: I'd rather start in rockwool, then put seedling into final pot...and NOT any drinking cups in between where you then need to transplant. (I can't say transplanting into Perlite/Verm being a lot of fun, way trickier than in soil).