I am running a 13kg propane bottle but with no way o telling how full it is so to be safe I would like to have a back up 6 kg bottle in the van , will this couple to my existing regulator , I do have a full small bottle of Butane under my bench ,if my 13kg of propane runs out could I change the regulator and run that to get me out of trouble I have a fridge , water heater , and cooker on board thanks in advance for your help