can you construct a trellis 12 inches above the pot ? this will get you the most yield for that lamp. that wattage has an effective depth of 12-16 inches.
when you don't train, your vertical growth pushes the the lamp away and decreases the lumen output by half every foot away from the lamp.
you can fortify with the spare cfl's as you mentioned and not trellis, you want to get the most for your power usage, that does cost money
heat generated also effect production.
the person that developed the Technique is named PH. he was able to yield 2 oz's per square foot with 40 watt fluros.
you can make your area 3'x3'= 9 square feet.
I get 1.5 per sq ft now.
You might want to consider cutting a clones now or in the next week.
you have a minimum of 11 days of vertical growth left in what is known as the stretch phase of flowering.