I think you should wait 1 week before changing veg nutes to bloom nutes.

Wait for the advice from other, more-experienced board members.

I know that Zandor uses a bloom 'booster' to 'kick' the plants into bloom... but I trully don't know if it's when 12/12 is switched, or if it's in the 1 week later nute change.

Hope this helps,

-turtle420