Did you try ga7, 'the gibb that regulates florogenesis'? Ive bern wanting to. Well that & florigen., which was hypothesized long ago and identified pretty recently but doesn't seem to be well characterized
Look at a product called Agra-Rouse. I can't believe it's not been discussed by anyone before and I only stumbled upon it a couple weeks ago, but it is a near perfect solution for what I've been wanting to try with starting seeds invitro.