I don't have a problem with tank to tank filling (I used to do it with oxygen) but I
would urge two extra safety precautions. When you are filling tanks which hold liquid,
like CO2 and Propane flash off (outdoors of course) a small amount of gas from the tank to
assure the presence of a gas bubble in the tank. Flashing off should not replace weighing
the tank but should supplement it. It should also be noted that almost any gas can be life
threatening if it fills an occupied space.
Greg