Until Insomnia arrives:
My first thought also. Might have that four letter word, Diet to be considered. With a focus on lower carbs for a start.Than when results are becoming positive and most fat is reduced, have them switch to something like a Mediterranean style diet. Exercise alone will not burn and reduce all that fat that much.
Might try lower ab rolls with elbows on the pads of a ab stand. Also knee up's while in that position, both legs or one leg at a time. Should be less strain on the lower back that way. This may bother some peoples lower back, but if the ladies can use a ab wheel, without any problem, than use one. Get's almost the complete ab wall. The more times you do a movement, even very slight at first, the more stimulation/nerve impulse are brought into action. Bring that muscle area to a more than a normal state.
If this works for the ladies, how about giving us all at GetBig a split of the fee you charge them? Only seems fair. Good Luck.