The good thing with this strain is that it seems to be mold-proof: all my plants got slightly affected but not this cute AK420. However, despite good cares and much love, she remained a short plant and produced small buds. I still don't know what went wrong.
What went wrong? Maybe she didn't like the 2 hours of light leak, maybe it's not a good strain for mainlining, or I probably had a poor phenotype... I guess I'll have to push my investigation forward by growing this one again. The "plate-training" technique is definitely something I will re-use later.