Hi all - Back with the continuing saga...

It's now been several weeks since the 400w HPS bulb blew and the plants were back under MH. (they were back under MH for about a week) Trouble is, I'm not getting any buds or flowering.
Sagarmatha's site recommends light schedule of 18/6 for full duration of grow, but 1 week ago I switched to 12/12 trying to force flowering... I was hoping to be able to get the flowers/buds to grow up through the trellis and keep the leaves under, but alas... NO FLOWERS, JUST NEW LEAVES.

They keep growing taller and I keep having to pinch them back, as they either get too crowded under a trellis, or they reach up to and touch the lamp itself.

Drip hydro -
5 Gal. rez.
AN MGB nutes
Sagarmatha Diesel Diesel Autoflower Fem.
PH - try to keep around 5.6
PPM - around 800
Humidity approx. 38%
Temp in box approx. 78-82 deg.

Lamp is air cooled, but still don't think it's a good idea for the leaves to be touching it!

Had some new leaves looking pretty yellow, but corrected with nutes.

Don't know how long to keep letting them grow before I decide they just won't flower. The grow box is only about 36" tall - grow area slightly less then 2.5 ft. I think each time I cut them back, it takes time for them to recover from the shock, but I just keep getting new leaf growth and no sign of flowers.

HELP!! Any 'tricks' known to force flowering?? I'm lost, and frustrated.

Thanks for any pointers - mrmcr