need to start flowering my bubblegum, what to do with my autoflower?

if anyone could let me know what they think, that would be great. i have a bubblegum plant thats almost 2 feet and due to space issues i am deciding to put her under the 12/12 schedule. the problem is, i got my 3 week old dieselryder in there with her. my question is this. what should i do with the deiselryder autoflowering plant? i have a extra light but its a 90watt ufo, not even close to the intensity of the 400watt hps that it is under now. or i can leave it in the flowering tent under the 12/12 (but i heard that anythin lessthan 18 on autoflowers produces badly). what to do? what to do? i know that this isnt an ideal situation but what would produce better? the full schedule under the ufo or the 12/12 under the hps?

I was in same boat my auto didnt get very big, but was some awesome smoke.Maybe another room with alot of cfls for few weeks then throw back under HPS.