Not sure how old your "green suitcase" is, but I'd test it out to see what it's burn rate is.  Most of the ones I've seen are gas guzzlers.  Add the weight of the extra gas you'll burn to the excess weight of your "suitcase" vs. the weight of two single-burner stoves and you'll find you are carrying *pounds* of extra weight.

2x32=64 which is half a gallon, not a gallon like somebody suggested.  I'd definitely bring a 3rd quart.

BTW if the stability of the suitcase is what is driving you to take it, you can mimic that stability by bringing a fire grate and setting two single-burner stoves beneath it.  Use fireplace rocks to set the grate on and to level it.

IMHO, single-burner stoves pay for themselves in many ways.  Reduced weight, reduced fuel useage, packability, reliability, etc.