I have tried to 24/0 method and have had great success. The plant was very stretchy.
My electric bill went way up. I am running 15 100 watt cfls.
I then went to my local hydroponics shop and purchased a product called Liquid light

h**p://www.dutchmaster.com.au/?language=english&page=product&product=LIQUID_LIGH T
I followed the directions to the letter on a 18/6 schedule and its better then a 24/0 schedule!
I will stand on liquid light. I will never grow tomatoes without it again.
Tomatoes are DENSE,THICK, And OOZING with flavor!
It runs about 60 bucks for a liter. expensive? maybe! But 1 table spoon per gallon of water and folar spray 2 times a week. It gets very cheap and well worth the effort and extra cost!
Hope I helped.