The thing is using 12/12 is sort of like tricking it saying hey look it's fall time to bud. It's a trick myself and many others have long used for photos.
My guess is this works with autos that are hung up (?) and need a push to get them to flip into budding.
Personally I like my seedlings to get 18/6 or even 20/4.
I'd consider a small led for the seedling that can supply it with say 200 to 300 PPFD.
There's a free app for phones to measure PPFD if you don't have it (PPFD meter or photone).
I use a couple of led strip fixtures for this and they only pull like 30W.
If that seedling container is small enough to easily move.. I guess you could try time it so you move it to say a window sill to get the extra hours of light but I'd watch for stretching (like 12 in the tent and 4 to 6 in a window sill).
Also I should have asked but are those seeds feminized? I can usually presex mine between 3 to 5 weeks. I'd hate to think your creating a lot of effort and it turns out it's a male